Planning of activity hours

Dear team

We have scenario in which we have production order without material CO07 and confirming production order with co11n, we have three activities in work center to capture cost senior management working hours,junior management working hours and admin hour heads.

Actually we want to plan activity hours of senior management and junior management they have worked on project ,how we can do this in sap and is it ok to have senior and junior management activities in one work center and cost center or we have to make two work centers and two cost centers for these activities?

Regards

Ramesh kumar