Resource usage basis type fixed and variable for same resource within same operation

Summary:

Resource usage basis type fixed and variable for same resource within same operation

Content (please ensure you mask any confidential information):

We have a requirement where for product FG, there is Operation OP-1 having resource RES1 which has fixed & variable resource usage. We cannot add same resource multiple times into same operation when defining the work definitions.

Could you please advise how do we achieve this?

Ex: Product FG

Work Definition : OP-1, RES1, Basis type Fixed with usage of 1.5 hours

OP-1, RES1, Basis type Variable with usage of 1 hour