let me make it clear what I want is u have

Server1 and two seperate instances

wherein db1 is mirroring with db2 ( endpoint MIrroring1)

now you have db3.....db4 mirroring session on same server(machine)endpoint(Mirroring1)

port number is 5022 for db1 ,portnumber for db2=5023

then what port number should be there for db3 and db4 that uses same endpoint (Mirroring1)for their mirroring session

Pls explain....