How to add user of one domain to the group of another?

I am new to openfire ,so I am not sure whether it is possible or not. Let me explain my requirement.

I have two different openfire server, say example1.com and example2.com. I have a user in the first server named user1@example1.com alog with other users. I want this user to be visible to all the users of the second domain. I can do this by adding user1@example1.com to the buddy list of users of second domain. But my question is is there a way other than this,so that if a new user is crearted in the example2.com , user1@example1.com should be visible to automatically. I have tried by adding user1@example1.com to the user group(only one group) of example2.com ,but when I add the user there will be an asterisk symbol near the added user and a note at the bottom which say Remote users or entities should accept presence subscription automatically. But user1@example1.com will not get any authorization request. Expecting a quick reply.

Thanks in advance to all.