hi, since I have two PSU's an Antec True 550 & Neo 500 I was wondering what is the best & SAFE way to connect this two to power supply to a single mobo with 3X crossfire.

I tried to look for a 2X PSU connector to 1X mobo connector but i can't seem to find them here in the shops & I'm not sure if it's safe to parallel 2 PSU together. has anyone tried this here before? thanks.