This is a fundamental limitation of VectorWorks that toobiloo has touched on though.
The current paradigm of symbols and PIOs means that when you choose to make your symbol using a PIO you lose the ability of that PIO to interact intelligently with the rest of your model. But if you use PIOs on their own they can become cumbersome and prone to mistakes when you need to edit them en masse.
One problem I've had with the loss of intelligence, for instance, when using a PIO-based window symbol was that it meant my windows no longer new which were the left and rights sides of the wall (so they didn't insert how I expected) and I couldn't use PIO features such as wall cavity returns. (and you have the same limitation with regard to records)
My immediate reaction was to suggest that VectorWorks should be altered so that symbols didn't stop PIOs from being intelligent, but, as Islandmon pointed out in response at the time, the behaivoural limitations of symbols can be viewed not as a weakness but as a strength, forcing awareness of precise insertions as well as protecting against undesirable global changes from outside the Resource's container.
So it seems to me that there needs to be a new paradigm altogether, one that makes the editing of PIOs en masse as easy as editing a symbol.
I've posted a wishlist item here:
http://techboard.nemetschek.net/ubbthreads/showflat.php?Number=77113