If I understood correctly, you could add a "6-way selector valve". Those have 6 ports, 2 that are for the pump, 2 for circuit A and 2 for circuit B. They are usually used to split a hydraulic circuit to use 2 implements. You choose between circuit A or B.
There are 2 "versions" of those kind of valves, manual ones with a lever that must be accessible to the user therefore it can be a pain to route all the hoses/tubes. The other models are solenoid controlled, you can install them anywhere and run a wire to a switch.
In fact it's what I want to do on my 1655, I installed the 3rd spool last year and I will install 3x 6-way selector valves to have 6 independent circuits. I will get:
- valve 1 circuit A : mid lift for mower deck
- valve 1 circuit B : front quick connect for JD quick-tatch lift (raise snowblower/blade)
- valve 2 circuit A : rear lift (3points) for misc accessories i.e. counterweight
- valve 2 circuit B : front quick connect for snowblower chute rotation
- valve 3 circuit A : front quick connect for JD quick-tatch angle (blade) AND quick connect at the rear of the tractor
- valve 3 circuit B : front quick connect for snow blower chute spout control
This is the one I plan on buying 3 of:
eBay - summit-hydraulics Hydraulic : Solenoid Selector/Diverter Valve, 13 GPM, 12v DC, #8 SAE Ports. The ports are SAE #8 which is too big for our tractors (we don't need 13GPM) but I've never found any with SAE #6 which would be perfect match for the 3/8" JIC. I guess the valve would have been smaller but oh well...