should I save on the amount of events needed?
This pretty much never makes a difference, unless you personally like to.
Do whatever makes the most sense to you.
It is recommended to separate peer, host, and common events so that they are clear, easy to read, and easy to identify problems and debug. Separating groups make it very clear cut which events should be run by hosts and which by peers, since hosts and peers have very different jobs and are the source of confusion and misunderstanding for a lot of multiplayer issues that come up regularly. However, if another way makes more sense for your own organization, that could be reasonable.
One thing that could be considered is that if the way your organize your events in a multiplayer project doesn't make sense to other people, it gets even harder to ask for help when you run into issues.