Welcome to TBN Mike!
While not familiar with the HST version of a 7100, I imagine it would be similar to the gear drive.
I'd unscrew the steel tube taking pressure from the pump to the 3ph valve, and cut an inch or two out at a convenient (predetermined) point.
Then bronze an elbow to each cut end and re-install.
Attach hoses to both elbows and connect them to a suitable spool valve, taking care to connect pump pressure to pressure and return to the 3ph line.
I think most if not all spool valves will need a pressure relief hose returning oil to the transmission.
Finally you'll need two hoses to your breakaways or alternatively you can attach the breakaways directly to the spool valve.