Table Copy/Synchronization

Hi,
I have two db servers primary/backup for which I would like to
synchronize a few tables.

Basically I need to check every 30 - 60 minutes if on the primary table
an update has beend one and add the changes to the backup server.

The problem is that some of these tables have foreign keys so I cannot
just simply drop and re-create them. I suppose I need to read the
primary table record by record and make the updates
(insert,update,delete) on the backup system.

Is there any tool or easy way to do that. I looked into the replication
but it seems to me an overkill and besides I don't wantto make any
changes on the dbschema except adding a table if necessary on the backup
system.

Thanks for any advise.
Alex