DataDomain Replication Using NBU SLPs' ( OST )

Hi Everybody , 

I need some information on below : 

We have one active netbackup master on our site A and we have media servers and clients on site B too for which Master server resides at site A . 

Our Short term backup destination at both sites A and B is Data Domain ( OST ) . Media Servers are 3 at each site 6 in total . 

Requirement is to have DataDomain Replicated on both Sites A>>B and B>>A . 

So how many SLPs' do we need to do that ?

Can we create an SLP to replicate OST DiskPool from A to B and vice versa or do we need to create SLP for each backup policy which takes daily backups on both sites ( daily incr or daily fulls )  ? 

Regards ,

Abhijit .