As Randy posted, a 3 way switch will work just fine. Just be sure to check what that open lead does when you flip to it. Lets say all the way away from you (the switch) is TH off, that is pretty simple. Middle would be throttle hold on so no blade spin, but what does all the way towards you do? Check this without blades. If it spools up (open connection), then you need to bridge the gap from the middle to the outside lead associated with the "UP" position. But make sure you know what lead is common and what lead is the signal and how they wire together.
If it keeps the motor off with the switch all the way up though, then you are golden...