Connecting motherboard power wires (24) to ATX power supply - any special connections needed/

I want to be able to connect a motherboard to an ATX/bench psu conversion. The supply has the extra wires of green (power on switch), blue and grey - the rest are the 3.3, 5, 12 and ground wires. Can I group all the same colored wires on the 24 wire harness into one connection and connect them to the proper power output and then connect the remaining green, grey & blue wires to their proper connections? So basically I'd like to make a total of 6-7 connections instead of the 24. Is there any issue with this?