User parameter shifting data from one sub data type to the other

need your help on some analytics that i'm trying to create; will try my best to summarize below:

1. input:
invoice data (transactional) with main columns: Spend (total amount), Supplier Type (Manufacturer, Wholesaler, Contractor, etc.) and Supplier (specific company name)

2. Aim:
the aim is creating a user parameter where the user can move a certain spend % (specified from the parameter) from one supplier type (or supplier) to the other. the different supplier types are part of Supplier Type data element as explained above and thus the problem im facing is creating a formula that allows that level of detail.
Aim is to make the dashboard as dynamic as possible (user trying different spend % shifts, etc.) and for different combinations

would really appreciate any help as this is key in trying to pitch something
thanks a lot!!