Robert,

In your schematic at the top of the thread... the highlighted (green) LED's will be dark when GP 1&2 are BOTH High OR LOW. But the trick is to keep track of that interaction with the other LED's that are also tied to either of those two pins.

If GP1 is high and GP2 is low then the Yellow LED will be lit, and vice/versa for the Red one.

Seems like to me it's time to draw up a good ol'e fashioned truth table.

With 5 bits (pins) in use it will have 2 exp 5 = 32 possibilities. The truth table will also help you develop your code.

Is this what they call Charlieplexing?? I've never done one of those, but that is how it seems to my feeble mind.

good luck