APEX

Hi gusy,
I need some help here

I have 5 applications and now I need to create a new one, and in this new applications i need to have links to these 5 already existing apps.
The problem is that i need to make the links parameterized, not hard coded.

So my question is: How can I get the ID of some application from another application?
And I need to get this ID without starting the first application ( the application whose ID i wonna get)

Is there some kind of sys table where are kept the application names and their IDs?

Thanks in advance
Tsveti