bi-directional AIR

I have two NetBackup 7.5 domains, each domain with a Master and a Media Server with MSPD. The idea is to have replication from Domain-A to Domain-B, and replication from Domain-B to Domain-A. Is it possible to achieve having a single Storage Server (on Media Server) and a single Dedupe Pool in each domain? Or do I need to add an additional Media Server in each domain?

Thanks!

I am new to AIR, so I might state something obvious...