Hi there, Ran! Thanks for getting in touch. 🙂
Great question. I do want to note first of all, though, that we are fairly limited in terms of helping out with custom development questions like this one. That said, we’d love to point you in the right direction if we can.
Venues are registered as custom taxonomies (tribe_venues), so I would imagine you are able to extend them to other post types when registering them. From there, you can use the tribe_get_venues() function to call the list of available venues in your filter.
Does that make sense? Will that work for you? Please let me know.
Cheers!
Geoff