Matrix user forums

I'm connecting my multiti programer to an X-Arcade game control with a proto board. The X-Arcade acts as a keyboard and uses a matrix that places switches in groups of four for output. So, the X-Arcade requires a separate ground for every group. I need to separate the two 9pin d-subs on the proto board into four d-subs with 5 pins each. How do I get four separate grounds for my switches with only two grounds from the multiti programer? I'll be doing J2 through J5 in the diagram below.

Thanks, Jeff

Hello Jeff

Can you not just link all of the ground signals together.