voltage - Positive and negative potential via two power supplies with common ground?

I need to use a positive and negative potential on a circuit including an instrumentation amplifier. My lab only has single supply power supplies (only offers positive voltage). I know that I can reverse the polarity and achieve a negative potential, but this means using multiple power supplies. (I am pretty sure that I cannot reverse the polarity on a single rail to fulfill both my negative and positive potential needs as this will cause a short). I do indeed need to tie the grounds for both supplies to one another, correct?