Configuration of databases in XA_Transaction

Hey i am trying to use XA_Transaction to commit changes in multiple databases… I want to know how to configure the databases while in XA_Transactions.
Suppose i make one connection of XA_Transaction type on 1 database then what about the other database???
How do i access tables of other database in the developer.

Its urgent…
Hope you people respond quickly…

Hi Guru’s

Am also having same query,Hope any body send the solution for this…

Regards
Arif