Tracking inventory with bin locations

Hi, I’m tracking inventory coming in and out of my warehouse.   I have a shipment table where i enter a record in each time something gets received OR shipped out of the warehouse.   When the material is received i have a field to enter the bin location that the product gets put away to.   That field is a lookup to a linked table where I’ve entered all of the available bin locations that can be chosen.   In the bin location table I’m tracking the project name in a field next to the bin location.  That way i can look at all my bin locations and see which projects are in which locations.  We need to know how many bin locations a project are taking up at a given time.   My dilemma is when material is being shipped out of my warehouse I’d like to be able to re-enter the bin locations the material is leaving and then update the bin location table showing that that bin location is now empty.   Is there a way to do that?  The shipment table has a field where I select “receiving” or “shipment”.  I feel like I need something that says if record = “shipment” then whatever bin locations I enter in that line that project is cleared out of the project field in the bin location table.