<a href="http://digital.ni.com/public.nsf/allkb/F4BB644ECCA595D886256FFE00722E29?OpenDocument" target="_blank">http://digital.ni.com/public.nsf/allkb/F4BB644ECCA595D886256FFE00722E29?OpenDocument</a>
This way, you are using efficiently your channels and you can use all the hardware resources independently for each of the signals.
Hava a nice day.