multi master replication Let us say I have a master(m) slave(s) replication. Now, in the scheme of things, I introduce another database/schema(foo) not associated with the master in any way and I want this schema to be replicated into the slave(s). Can I do this?

AFAIK, this cannot be done. What is the best way to pull this off? The reason I want to do this is I want to join tables from foo with s/m. 

The data replication need not happen in real time, can be a daily cron job too. Is mysqldump the way to go? Is there some hack that I can pull off?
I don't know if it's the best way, but you can always pull the binary log and let it execute somewhere else.

A MySQL node can be Master AND Slave at the same time, but it cannot be Slave of two Masters.

See this similiar post:

https://stackoverflow.com/questions/1576603/is-it-possible-to-do-n-master-1-slave-replication-with-mysql