assigning usb midi in midi device manager

hi,i have 8 usb/midi leads connected to pc running cubase 7.5,they appear in my windows device manager and in cubase but are all called the same.
i cant seem to be able to assign a midi/usb in midi device manager other than the one at the top of the list,if i click on another ,re-open the drop down menu it will revert back to the top one.
if i add a midi track in the project and select all midi inputs and select one of the midi/usb’s it will play that one i.e i start hearing audio from a hardware synth,this would work but they are all called usb/midi.ideally i want to create an external synth and when i load up in track it has the righ usb/midi already selected.

hope this makes sense