Material Replication

Hi,

We are replicating Materials from ECC to SRM using R3AS.

We have filters in SRM (R3AC1) that allow specific materials to be replicated.

For example say materials A and B were replicated.

Now I change the filter to only allow A flow through.

BUT This does not delete B from SRM.

Also if I delete all materials and do initial load again...GUIDs are changed affecting the existing Shopping Carts?

How do I ensure that what is filtered is only visible to users when they create new carts while old carts are unaffected?

Thanks,

Nikhil