I use the RF-602 triggers for all sorts of things - firing studio flash, hot-shoe guns, or remote triggering of the camera. All you need is the right lead. They come with a 1/4in jack to 3.5mm adapter but I don't know about short or long fitting for Portaflash.
Presumably you are using the sync lead to fire one head which is then triggering the others by optical slave. A radio trigger will work in just the same way and you can also integrate hot-shoe guns into the set up by adding an extra receiver unit to each flash (assuming they don't have an optical slave built in, which many do not).