What is shown is a process known as 'Charlieplexing' after the inventor Charlie Allen, who works at Maxim.

http://en.wikipedia.org/wiki/Charlieplexing

There is a good intro at http://www.instructables.com/id/ERHG974F1ZM4KIR/

I used this to help me do a 12 led display with only 4 lines from a PIC using PBP, so it is possible. The trick is to drive the port high or low or set the TRIS bit to make the pin High Impedance (floating).

Now I am not sure I understand your question, but the links might give you enough to work out what you need to ask.

bill.