In the Nozzle input Box there is a tick box "Is The Nozzle Connected to another Nozzle" If you tick that you can add an additional nozzle to the pipe work.

It generally doesent look very good visually tbh but its how you would do it. It doeent work very well if you have pipework with bends coming out of the heads as where you can place the additional nozzle is pretty limited.