A group is not a symbol and should not be used for repeatable things. Groups are useful for collecting a bunch of stuff together, like a section or an elevation, but they have no use in your library files as you can’t access groups with the Resource Browser (the main tool for accessing your library).
Creating a symbol.
There is some great protected information here that is only available to paying subscribers. You must be an active paying subscriber to see it, but you can Subscribe here.