Enterprise Vault, Vault Stores

Hi

We have 4 Journal Archive Servers

On each Journal Server we have 7 Vault Stores,  with 6 Partitions in each Vault Store.

E.G.

EVJRN001VS1 (with partition 1-6 in it)

EVJRN001VS2 (with partition 1-6 in it)

Etc to EVJRN001VS7

Each Partition within a Vault Store is set to Roll over at 1% free and works fine,  but what I need to do is roll over from EV1JRN001VS1  partition 6, to EV1JRN001VS2  Partition 1...  how do I do this?

Thanks.