Conference with peer registered in another server


I need to set up a conference between peers registered in different asterisk servers. I have server A and server B. I am controlling the calls and connection to conference rooms to my server A by AMI. So,I am able to set peer 1 and peer 2 (registered in server A) in a conference room configured in server A, but I also need to connect peer 3 (registered in server B) to the same room.

By now what I am doing on server A is just a simple dialplan with the entrance:

[ext-conference] exten => 1234,1,MeetMe(${ROOM})

So, I through an Originate Action I can set peer1 and peer 2 in the conference but as peer 3 is not registered in that server A I understand that I should execute a different exetnesion for peer 3 or even maybe exeucte something in server B, but I don’t know what exactly.

I am quite newby on this, so any help will be much appreciated.

Thank you!