Taking things one at a time with dots netcode

Hey guys,
I hope I am not duplicating any other discussion here:
I decided to start and try out netcode with dots stack by making an RTS game mechanic. Also, I know for now the sample project and the team efforts are into Shooter kind of games and it is also promised in the future that the RTS approach will have it's own attention.

So in this scenario I started altering the cube-sample-netcode project for my quest purposes.

My question (TLDR):
Can anyone help me with how to send onetime input to the server ( eg. "unit selection" )? - as opposed to during the GhostPredictionSystemGroup ( which is fitted for movement for example)

Context:
While the net-cube example shows how to sample the input while predicting the cube moving, I am interested to just send the selection info to the server - I would like the server to make the selection of units (and the units are afterward synchronized with all the clients).
I think it should be the same situation in the shooter example ( DOTS Sample ) - when the user sends PrimaryFire but I cannot seem to find how to integrate those parts of code into my project that is almost as netcode-cube sample.


Thank you!