I don't believe there is a way. Nvidia has hybrid SLI and ati has hybrid crossfire that if you have a motherboard that supports it, you can install a lower end nvidia/ati card and have the integrated card give the dedicated card a small boost.
As far as I know for ati the common boards that support hybrid crossfire are the 780, 785 and 790. I'm not sure about the older 770 or the new 890.
Nvidia, I'm not too sure but I think it has to be a geforce 9100 and up. Correct me if I'm wrong.