This very topic has been discussed recently over at the bp. From what I gather, it is doable with the usage of some relays and creative wire routing etc, but it is far from being as simple as splicing a wire here and there. The side markers are single filament bulbs, and the front ts/park bulbs are dual filament, so there is a grounding issue to overcome when a ts is active at the same time that the head or park lights are active.