Hi there Klaus and thanks for getting in touch! We’re stoked you’re considering the Community Events plugin. 🙂
Excellent question. For the time being, all venues and organizers will be available to select from the event submission form. You can set a default venue and organizer if you have The Events Calendar PRO activated and installed as well, but hiding specific venues and organizers themselves would likely take some custom development to achieve.
Does this help answer your question? Please let me know.
Cheers!
Geoff