Combo Box To Sort Already Sorted List Box

Ok what I have is a List box with four rows. (Name, Assignment, Location, Description) These are all labeled with a frame at the top that when that frame is selected that row is put into alphabetical order.
The next thing I have is a combo box which also sorts the List box by "major location". The combo box has the following (All, Fort Mills, Corporate, Pequot Lakes, Savage, Retail) When one of those is selected the location row then shows only one of the following locations and the others are removed.
Here is where the problem comes into place. I want to be able to select a major location, then be able to sort with the frame. When I select a major location, and then click on the frame, lets say "Name" the list resets back to everything from that table and not just that certain "Major Location" that I have selected. I need to sort whatever is selected in that "Major Location" by whatever is selected in that frame. thanks for any help, I know its a hard one.