I don't comprestand why you're using a PIC. Transistors or relays will be easier than a PIC for just switching on and off LEDs.

If you're stuck on using a PIC I'm betting you could use a 12F675 and I'm wondering if this will work. Why can't you make a voltage divider and set a pin at 1/2 of VDD which should be ambiguous with the port set to digital. Then you could monitor the same input pin for a high or low. This way you could use two pins for four inputs and have the other 4 outputs free for your LEDs. Well, you only need 3 ports to switch 6 LEDs but that's another thread.

Caveat is I've never tried it and wonder if it will work. If I get time I'll throw it together today and see if it works.