Hello,
Currently this functionality is not supported by the system.
You can assign workers to multiple positions, but only one worker can be assigned to a position at the same time.
Please refer to: docs.microsoft.com/.../departments-jobs-positions
Only after one worker position assignment is expired can another worker be associated with the same position. Otherwise the assignment start time and end time will overlap and the system will not allow that.

You can create two identical positions to accommodate two people.
Regards,