I am having the same problem. I just spoke to someone at Square asking if there was anyway to sell for someone else without it showing as an income on my end. He said not at this time but having some type of "consignment " category on our POS was a good idea and he would turn in the request. Hopefully this will become available soon because I know a lot of sellers and vendors having the same issue and that is one reason they won't switch to Square.

I would love to have a more convenient option for this with Square as well.  Our office is considering hiring another consultant whose receipts, billing and everything would be separate but then we would either have to constantly log-in and out or purchase a separate device to run the POS from.  It would be nice to be able to switch more easily, like separate tabs (I don't suppose one could install an app twice on an iPad?). Does anyone know a POS that is able to do this?  Two bank accounts, one POS.  Thanks!

@Nanica54, One way to run to locations in the same account on the same iPad would be to run the Square beta and the App Store version simultaneously.  you can log in and chose a location in each app.  we do this with our wholesale and retail divisions.