Adding Networked Var to existing items

Guys, I want to add a set of networked variables to “func_door”, “func_door_rotating” and “prop_door_rotating”.

The problem is, I have to call NetworkedVar inside the ENT:SetupDataTables function - except there isn’t one that I can override for entities declared within hammer.

I thought about creating a new entity and deriving it from func_door (for example) and then replacing that entity with my one once the map loads. Will that work? Maybe there is a better way.

What should I do?

NetworkVars are in Lua, you can easily simulate them on other entities I believe.