SAP and CRM Roles

My requirement in the org is as follows:

There are 2 users in a location. User A and User B

A has 4 roles assigned to him. Ex. R1, R2, R3 and R4. User B is assigned different 2 roles, say S1 and S2.

On weekends only, User B will have roles R1 to R4. Come the week start, these roles are not to be used by user B. There are many users with this requirement and week on week, we have to instruct roles team to make changes.

Can there be a way to assign these roles with end date as 31.12.9999, but user B can only use roles R1 to R4 on weekends and auto change to roles S1 and S2 at week start.