dblink ,dblink_exec not participating in a Transaction??

How I can make dblink to participate in transaction so that remote changes made by dblink can only be committed if only local transaction succeds.

Here is my current scenario:

I am using two databases A & B. In Database A, I have trigger procedure written for a Table . In this trigger procedure, I use dblink_exec to update a table in the other database B.
The problem I am having right now is my trigger procedure currently participates in a transaction. If Transaction rollsback: whatever trigger procedure modified in database A is getting rolled back whereas Chages made to a table in Database B using dblink_exec are not.
Note: Transaction can be rolled back due to excpetions any where from main db client which updates a table in database A .

So my question is there a way to tell dblink_exec to participate in a Transaction. This way commits wont go to table in database B until transaction completed succesfully.


I appreciate any help,

thanks,

---------------------------------
You rock. That's why Blockbuster's offering you one month of Blockbuster Total Access, No Cost.