[Cutter]

I would use your 2 Elinchrom D-LITE 4 softboxes and their in built sensors to light the background and get a nice even light. Making sure its a coulple of stops lighter than your subject. Then use your trigger on your 580s with softboxes to light your subjects. The 580s will trigger the sensor on your 2 Elinchrom D-LITE 4 softboxes ( I think)