Financial Modelling: Staffing Inputs - how to toggle both starters and leavers

Hello, I hope this post finds you well.

I am trying to figure out how to model staff joiners and leavers for a company model.

I need to be able to add a leaving date, not just joining date e.g., if this month has a new starter, put '1' in the cell, but if they leave in a future month, return all future cells to '0'.

I have managed the first part - adding a 1 based on new joiner date, but I can't work out how to remove the 1 for future months if this hire was to leave.

This 1/0 toggle drives whether to pick up salary, pension, medical workings.

Thank you in advance.

Maybe:

=IF(AND(N$1>=$C6,N$1<=$D6),1,0)

No... more like this:

=IF(AND(N$1>=$C6,N$1<=IF($D6="",10^10,$D6)),1,0)