Limit records available in a lookup drop-down menu

Limit records available in a lookup drop-down menu

I have a lookup from another form to present choises od delivery days in a drop down menu. I added a yes-no field in that form to limit the choices. For example. if the monday delivery is not available anymore, I as admin will check that yes/no box and only the other days in the drop-down menu will appear in the lookup.

I am sure there a way to do that, anybody ?

Sylvain