Обсуждение: Replication

I checked gborg.postgresql.org, but I'm still not clear about the following:
I have a configuration that backs-up the database on server A every night
and the file is stored on server B (200 miles away, over a T1). Upon
arrival, the db is restored on server B, so, in the morning, A and B are
identical.
The working server is A. Users at location B actually use server A over T1
for normal operations.
If the T1 fails (assume overnight, after backup was transmitted), users at
the two ends can work off the local server.
If PG was installed without replication support, is there a way to
synchronize the two databases after each end has made changes to them?
Thank you all.