Check Data in Subform before closing Main form

[new_2_prog]

I have a main form ShiftInput and I have a subform ManHours.

Before the main form closes I need to check if there are ManHours entered.

Structural background
tblMaster = ID_Master, ShiftDate, Dept, SupID, Shift
tblManHours = id(auto#), MasterID, SysProcess, HrsDirect, HrsIndirect
lst_Equipment = id(auto#), Dept, SysProcess, AvailMin

So based on the Dept in the Main form (based on tblMaster) only certain SysProcess can be selected (lst_Equipment), I need to then check to see if any or all of these SysProcess are in the subform ManHours and if not prompt the user to go to the subform and enter.

I am not sure how to tackle this one, if an array is the right way to go but since I have to join some tables I am not sure how to go about it.

Thanks!