If you continue to bleed and refill the master cylinder with new fluid until what is bled goes from dirty to clean, this is essentially a flush. Only thing I'm not sure about is the ABS system. Is that a branch off of the circuit or is it in series?
Flushing a system with ABS is harder due to the ABS unit being inline with the system. You can do a remove and fill flush rather easily. Remove the cap from MC and suck out all the nasty stuff with a large syringe type pump (you can get these at Discount Auto,just ask for the 2 cycle oil mix syringe). Put a little fresh fluid in the MC to lossen up the crud and suck that out. You can get creative to remove junk inside but dont let any loose crud stay in. Fill with fresh fluid and do the rest just like a normal brake fluid change. If you turn the key off and on a few times it will cycle the ABS pump. Next is the fun part. Find a dirt road thats not crowded slam on the brakes hard and do a few ABS cycles. Dont go any faster than 20 MPH and make sure car isnt pulling to one side or other. The ABS will chatter and try and do its job and at the same time be flushing itself with fresh fluid. After a few of these cycles go back and flush the system again. If you have a Tech 2 scanner you can do all this without the dirt road panic stop thing. I do a reverse flush last to make sure all the air is out,but it takes specialized equipment. Keep safety in mind when doing any panic stop/tests.