Alias is not in GAL

[Sprengel]

I've got that problem:

MyName@example_one.com is my first address.

On my second domain i have the alias:

MyName@example_two.com

Everyone with addresses ending with example_one.com can find me in the global address list.

But on the other domain nobody can find me. For example:

user1@example_two.com can find user2@example_two.com in GAL, but user1@exampe_two.com cannot find MyName@exampe_two.com (my alias).

What can i do?