Transactions?

Hi,
I have a basic question on JDBC for postgresql.

Here's my scenario.

1) Start a transaction.
2) Get ONE OR MORE connections and perform operations(on different objects).
3) If anyone fails, rollback all the operations, else commit
   all the operations.

I read that Postgresql doesn't support distributed transactions.
But that is not a problem for me. We are having all the operations
in the same database. Previously we were using EJB and Oracle and
it was working fine. Now, we have plain Java(not EJB) and postgresql.
So we thought of using some transaction managers like tyrex.
But they ask for JDBC drivers which support transaction(XA, I think).
I dont see any XA related files in JDBC driver I downloaded from
site.(jdbc.postgresql.org).

How to solve this problem?

Regards,
Balakrishnan.