It's probably just me, but I'm wondering if this is the right interpretation or description. Are you talking about the standard RETURN valve?
Standard Jandy functionality does not require specific jets for what they call "Spillover". If you think about the 2 basic JVAs (Intake and Return), there are 4 combinations of the 2 valves that give you the following functionality.
1. POOL MODE (100% from and to the Pool)
2. SPA MODE (100% from and to the Spa)
3. SPILLOVER (FROM POOL through INTAKE valve, TO SPA through RETURN valve)
4. DRAIN (FROM SPA through INTAKE valve, TO POOL through RETURN valve) - this is commonly used for servicing the spa jets, etc.
So, the SPILLOVER mode that Dip Switch #3 triggers usually sends through the RETURN valve to the normal jets.
Again, a picture of your equipment pad would really, really help narrow down the discussion!!