I have an employee, who received an initial starting bonus of $50k.
This value will be static from day 1 to day n and will never change. I
want to see the intial starting bonus, but any sets higher than the
employee dimension will need to aggregate the starting bonus. Is there
an easy way to do this?

If I just look at the data from an employee's perspective, I can do
this by making the measure a Min, Max, or Avg Aggregate function. But,
if for instance I want to view the data from the perspective of
departments, it would need to sum() the data instead (which min/max/avg
don't do).

If I make the starting bonus a member property of the employee, and a calculated measure off the member property, it aggregates the data when it shouldn't.