APM and multi-domain

Hello, I am trying to create a login page on APM. I have 3 different AD domains. What I want to accomplish is create a login page so when a user logins in they will login with either domain\username or username and a drop down for the user to pick a domain. So all 3 domains will login to 1 server that will accept all three domains. has anyone set this up before that can point me in the right direction? All I see out there is SSO to mulit-domains.. which is not what I want.

 

AP = Start >> Logon Page >> AD Auth

 

• I noticed that in APM and AAA AD you can create a domain then add DCs. Can I add DCs from all different domains here?

Thanks in advance! Ken