I agree with Melanie re the additional logic. I would place latches on all of your output ports and link their enables to two pins on the PIC - for instance, require the enable code be 01 to activate your output. This way the chances of random activation of your output are drastically minimised.

To save a pin, you could use a pulse train on a single pin to count up to a certain value - thus activating a pin on a counter that would activate the latches. You might also even rig up a 555 timer to do a similar thing athough the implementation might be a bit convaluted.