How to setup customer site to assign different payment method for each BU without creating duplicate

Summary

How to setup customer site to assign different payment method for each BU without creating duplicate address

Content

We have a customer with one address and it deals with 2 different BU's. Each BU has its own Direct Debit Method setup for automatic receipt creation. Since customer has one address we can only assign one payment method. Fusion now uses Address Sets instead of BU while creating a site, and it not possible to assign multiple BU to same address to create separate sites without the need to create duplicate address.

What is the best approach we can follow in the scenario to have separate site for each BU without the need to create a duplicate address?