Yes you can share a single transducer via Ethernet.
Each unit would need the AS EC QDE Ethernet adapter and then an Ethernet cable to go between them.
2' is the shortest Ethernet cable available AS EC 2E
When you do that, turn SONAR OFF on the unit that doesn't have a transducer connected to it so you won't damage the unit processor by not having a load on the sonar circuits.
For the unit with no transducer, select the other unit as the 2D source, Advanced source, and Temp source in the Ethernet menu.