diff --git a/oauth3.core.js b/oauth3.core.js
index 3660ed9..0c71dc8 100644
--- a/oauth3.core.js
+++ b/oauth3.core.js
@@ -1086,7 +1086,11 @@
 
     var result = {
       _clientUri: OAUTH3.clientUri(location)
-    , _providerUri: null
+    , _identityProviderUri: null
+    , _resourceProviderUri: null
+    , _identityProviderDirectives: null
+    , _resourceProviderDirectives: null
+    //, _resourceProviderMap: null // map between xyz.com and org.oauth3.domains
     , _init: function (location, opts) {
         var me = this;
         if (location) {
@@ -1094,13 +1098,20 @@
         }
         if (opts) {
           if (opts.providerUri) {
-            me._providerUri = opts.providerUri;
+            me._identityProviderUri = opts.providerUri;
+            me._resourceProviderUri = opts.providerUri;
+          }
+          if (opts.identityProviderUri) {
+            me._identityProviderUri = opts.providerUri;
+          }
+          if (opts.resourceProviderUri) {
+            me._resourceProviderUri = opts.providerUri;
           }
           if (opts.session) {
-            if (!me._providerUri) {
+            if (!me._identityProviderUri) {
               throw new Error("'providerUri' was not supplied");
             }
-            opts.session.provider_uri = me._providerUri;
+            opts.session.provider_uri = me._identityProviderUri;
             opts.session.client_uri = me._clientUri;
             me.session(opts.session, opts.sessionId);
           }
@@ -1108,35 +1119,62 @@
       }
     , init: function (location/*, opts*/) {
         var me = this;
-        var p = OAUTH3.PromiseA.resolve();
+        var p1 = OAUTH3.PromiseA.resolve();
+        var p2 = OAUTH3.PromiseA.resolve();
 
         me._init(location, opts);
 
-        if (me._providerUri) {
+        if (me._identityProviderUri) {
           // returns directives
-          p = OAUTH3.discover(me._providerUri, { client_id: this._clientUri });
+          p1 = OAUTH3.discover(me._identityProviderUri, { client_id: this._clientUri });
+        }
+        if (me._resourceProviderUri) {
+          // returns directives
+          p2 = OAUTH3.discover(me._resourceProviderUri, { client_id: this._clientUri });
         }
 
-        return p.then(function () {
-          return OAUTH3.discover(me._clientUri, { client_id: me._clientUri }).then(function (clientDirectives) {
-            me._clientDirectives = clientDirectives;
-              return clientDirectives;
+        return p1.then(function () {
+          return p2.then(function () {
+            return OAUTH3.discover(me._clientUri, { client_id: me._clientUri }).then(function (clientDirectives) {
+              me._clientDirectives = clientDirectives;
+                return clientDirectives;
+            });
           });
         });
       }
     , setProvider: function (providerUri) {
         var me = this;
-        me._providerUri = providerUri;
+        return me.init().then(function () {
+          return me.setIdentityProvider(providerUri).then(function () {
+            // TODO how to say "Use xyz.com for org.oauth3.domains, but abc.com for org.oauth3.dns"?
+            return me.setResourceProvider(providerUri);
+          });
+        });
+      }
+    , setIdentityProvider: function (providerUri) {
+        var me = this;
+        me._identityProviderUri = providerUri;
         return me.init().then(function () {
           // this should be synchronous the second time around
-          return OAUTH3.discover(me._providerUri, { client_id: me._clientUri }).then(function (directives) {
-            me._providerDirectives = directives;
+          return OAUTH3.discover(me._identityProviderUri, { client_id: me._clientUri }).then(function (directives) {
+            me._identityProviderDirectives = directives;
+            return directives;
+          });
+        });
+      }
+    , setResourceProvider: function (providerUri) {
+        var me = this;
+        me._resourceProviderUri = providerUri;
+        return me.init().then(function () {
+          // this should be synchronous the second time around
+          return OAUTH3.discover(me._resourceProviderUri, { client_id: me._clientUri }).then(function (directives) {
+            me._resourceProviderDirectives = directives;
             return directives;
           });
         });
       }
     , checkSession: function () {
-        return OAUTH3.hooks.session.get(this._providerUri);
+        return OAUTH3.hooks.session.get(this._identityProviderUri);
       }
     , login: function (opts) {
         var me = this;
@@ -1148,16 +1186,16 @@
         opts = opts || {};
         opts.client_uri = me._clientUri;
 
-        return OAUTH3.implicitGrant(me._providerDirectives, opts).then(function (session) {
+        return OAUTH3.implicitGrant(me._identityProviderDirectives, opts).then(function (session) {
           me._session = true;
           return session;
         });
       }
     , session: function (session, id) {
         if (!session) {
-          return JSON.parse(JSON.stringify(OAUTH3.hooks.session._getCached(this._providerUri) || null));
+          return JSON.parse(JSON.stringify(OAUTH3.hooks.session._getCached(this._identityProviderUri) || null));
         }
-        return OAUTH3.hooks.session.set(this._providerUri, session, id);
+        return OAUTH3.hooks.session.set(this._identityProviderUri, session, id);
       }
     , request: function (preq, opts) {
         opts = opts || {};
@@ -1165,10 +1203,10 @@
         preq.client_id = this._clientUri;
         preq.method = preq.method || 'GET';
         if (this._session) {
-          preq.session = preq.session || this.session(); // OAUTH3.hooks.session._getCached(this._providerUri);
+          preq.session = preq.session || this.session(); // OAUTH3.hooks.session._getCached(this._identityProviderUri);
         }
         // TODO maybe use a baseUrl from the directives file?
-        preq.url = OAUTH3.url.resolve(this._providerUri, preq.url);
+        preq.url = OAUTH3.url.resolve(this._resourceProviderUri, preq.url);
 
         return OAUTH3.request(preq, opts);
       }
@@ -1177,16 +1215,16 @@
         opts = opts || {};
         opts.client_uri = this._clientUri;
         opts.client_id = this._clientUri;
-        opts.session = OAUTH3.hooks.session._getCached(this._providerUri);
+        opts.session = OAUTH3.hooks.session._getCached(this._identityProviderUri);
 
-        return OAUTH3.logout(this._providerUri, opts);
+        return OAUTH3.logout(this._identityProviderUri, opts);
       }
     , api: function (api, opts) {
         opts = opts || {};
         opts.api = api;
-        opts.session = OAUTH3.hooks.session._getCached(this._providerUri);
+        opts.session = OAUTH3.hooks.session._getCached(this._identityProviderUri);
 
-        return OAUTH3.api(this._providerDirectives.api, opts);
+        return OAUTH3.api(this._resourceProviderDirectives.api, opts);
       }
     };
     result.authenticate = result.login;