Hey Stefan,
Thanks for reaching out to us!
If I’m understanding the question here, it sounds like you’re creating the Venue (without importing from Facebook) and are wanting future imports from Facebook for that venue to be attached to that Venue rather than importing a duplicate of that venue detail?
The simplest way to get the best result here would be to do a single import of an event from each of the venues that you’d like created. When importing, there is an associated Facebook defined ID that gets stored for the venue that we check against when importing in the future.
Let me know if this helps.
Thanks!