Great question!
Answer - I'm not sure. It 'might' work as long as only one pump at a time was turned ON, but some pumps allow water to flow through them even when not in use. This would be when on plane and running, as water is forced through the scoop. The concern here is 2 things, would water thru the non-running pump inhibit operation of the one that is running? I'd also be concerned about losing a hose (due to pressure) off the pump that wasn't running, thereby filling your bigle up with water.
You could always do both a "T" and a manual in-line shutoff valve in each line, as 3-way valves (1 source - 2 feeds) cost $60 or so. A PVC "T" and simple valves at Home Depot would be around $16 for all, I'd guess.