Oz,
okay, this is what I know. Most of it came from 'the horse's mouth' so to speak, so I'd say the accuracy is pretty good.
Apparently the ground staff are Aerocare. They just wear the DJ uniform. Some of the Aerocare people also apparently work for WAC (or something, don't ask me how that works). I think at first the new employees do duties for Skywest (in the XR uniform), I.e. check-in, boarding etc). Once they have been there awhile they then get to 'move up' to doing the same thing for DJ once they are trained properly. I guess this is so DJ don't have "newbies", then again I think lately a few have gone direct into doing work for DJ judging by some of the boarding calls I've heard!
So they can pretty much put them where they're needed, though I think once they are in with DJ that's what they do.
You will still see the more senior staff in the Aerocare uniforms though, and they switch between the two I think. Perhaps someone else may be able to shed more light???
I know also that some of the AC staff are trained as relief crew in case any of the DJ crew go sick while in Perth, and they can cover for flights back to Syd, Mel, etc. Apparently the staff that do this go through the same training as the regular DJ staff.
As for Skystar I don't know a lot about them, I was told they do the handling for Intl by a girl who works for AQIS. I do know they are connected to or are a subsidary of Monadelphous. (the mining/recruitment mob)
Hope this helps!!!
Sky