My brother works with me every now and again so I set this up the other day...
The male end plugs into my vans outlet hose, and then the two female ends can be used to plug into seperate hose reels, all working off of one pump.
It works really well, the only thing is that I have to increase my digital varistream to about number 7 and then when one of us turns our hose off the other gets a really fast flow - It means I can tell when he's slacking though!
Andy