Item financial planning with supplier detail

Hello experts,

We are configuring PPM 6.10 and I have a particular requirement from my Customer dealing with Item planning process.

My client would like to plan costs at a supplier lever in order to agregate budget per supplier and be able to discuss and optimise purchasing.

It is not possible to make it using Types nor Categories because it should be dynamic (hundreds of suppliers ...).

Idea ? I thought about using Easy Cost Planning in Project level and then agregate Financial on Items ...

Thanks