S4Hana - Business Partner : Customer & Vendor Linking

Dear All,

Customer and Vendor have been created in 2 different business partners master record. Hence the Customer number shows as 2000 and Vendor number shows as 3000. User want to link both of them for Customer & Vendor are same scenario.

But i able to link the vendor 3000 with customer 2000 in Vendor BP. But customer BP does not accept the Vendor.

Please clarify on this