Account Linking With IdentityServer3
<p>I'm investigating IdentityServer3, and I'm wondering if there is built in support for a specific scenario that I'd like to implement.  The flow is as follows:</p>

<ol>
<li>User signs into IdentityServer, using Identity1 and is issued access
tokens for our application.</li>
<li>User navigates to a "Link Identity" Page,
where they can choose to link an identity to their account </li>
<li>While signed in with Identity1, the user enters credentials for Identity2
to prove that they own Identity2 </li>
<li>Using the Identity2 information, my application links the two accounts
to the same account.</li>
</ol>

<p>Is this type of account linking supported OOTB with IdentityServer3, and if so, which features should I use.</p>

<p>If not, any advice on how to proceed?  The main challenge that I'm unsure how to pull off using IdentityServer3 is handling the "double sign in" (e.g. authenticating as Identity2 while already signed in as Identity1)</p>