I doubt they'll work on the same channels Pete but I've wondered about doing a similar thing with my Skyports. I dont' know about the 602s but when I had the original chinese cheapo triggers the transmitter had an input jack so that you could fire it from a camera which had no hotshoe but did have a PC port.
My idea is to use one of the Skyport receivers to trigger the next transmitter (sort of like a daisy chain) which then triggers multiple 602 type receivers, cheaper than multiple Skyports. You can also get adaptors which give you three outputs from one cable input so it would be possible to use the Skyport (or PW) in your case to trigger a flash and the extra transmitter.
I've not tried it yet because I gave my cheapo triggers away but I don't see why it won't work. The only problem I can think of is that it might induce an extra delay which means you might have to drop your shutter speed from 1/250 to 1/125 maybe, not really a problem if you're shooting in dim light but more of a problem if you're shooting in bright light. The other side effect of any delay might be the discharge time of a full power flash so the second set of flashes triggered by the 602s might be better off in the lower powered positions than putting them in the nuking positions.
