title: Identity Server - multiple STS
body: <p>I have two groups of api applications (group 1: api11, api12; group 2: api21, api22) that are used by two different groups od javascript applications (group 1 and group 2). Each api group has different domain and use different instance of Identity Server (also each identity server has different domain). Business requirement is that user logged in to any application from group 1 can use any app from this group but can't use app or api from group 2.</p>
  
  <p>Under the hood both api1 and api2 often needs to talk to the same microservices. What I want to achive is to make microservices accessible with access tokens issued from any of the identity servers (used by group 1 or group 2 app). Is there any way to achieve this? For one identity server I can use UseIdentityServerBearerTokenAuthentication but as argument I can pass only one Authority there. </p>