Vendor acct group and number range in the MDC vs MDS

IN MDM 3.0 when a new BP with vendor as role is created via UI in MDS the vendor is created with a generic BP number range in the MDS. The down stream MDC's all have different vendor account groups with different number ranges assigned in each MDC.. example...

client type of vend acct grp num range

MDC1 purch vendor com2 1000000-1999999

MDC1 acct vendor act1 2000000-2999999

MDC2 purch vendor pur1 2400000-2499999

MDC3 purch vendor POV1 3599999-3599999

How does MDS know when it distributes the vendor to the MDC's what account group and number range to create the vendor with in the MDC's. The MDC cannot change all its existing master data that has been created already with the account groups and number ranges becuase field variants have been established. Where is this mapping contained MDS or XI and how is it done.