Running two ipaq's simultaneously on one compter

I would like to use two ipaq's on my computer at the same time. Unfortunately MS active sync will only recognize one device at a time. Any workarounds, settings or third party software that will allow me to do this? I have a program that uses both ipaq's all I need is to get the computer to recognize both ipaqs at one time. Both ipaq's are the same model rz1715 connected via usb to hp a1750n running MS Vista.
Thanks in advance and Happy New Year to all!!!

 

Try running another system is a virtual machine. VMBox is a little quirky to get USB working,b ut it does. VMWare USB is easier.