The only "practical" way is run another aux line off the machine that runs the mulcher. That can be set at its own PSI rating. Running at max GPM isn't the issue, its the pressure that matters. I don't know if BC sells that or if it done on that machine where it is older. The pump needs to have another hyd valve. Sometimes they come that way, I just don't know if that machine did or not. If a second aux capability was an option when it was new, I would say that it has that valving. BC or maybe someone on here knows the answer to that.