Multiple rates for 1 resource and 1 instance in maintenance

Hello, in Maintenance Management Module, I have the following scenario:

Our client has multiple customers.

He executes the same maintenance work orders while assigning the same resource and the same instance. But the thing is, that for some of them, the rate per hour is X, and in the other hand for other customers, the rate per hour is Y.

How can this be achieved?

Do I have two create two resources with 2 different rates? Or can I have two rates for 1 resource?

Please explain.

Thanks