Looking for the best solution for vendors with multiple locations

Thanks for your reply Ihor! I dont need the map or radius-feature, so i could use the Select-attribute.

However, im struggling to figure out the following:
Vendor 1 offers their services in City A
Vendor 2 offers their services in City B
Vendor 3 offers their services in City A & all other cities

I guess if i use multiple select and select all the cities on that vendor, it will show a huge list when i want to display the “main” city they are in, so thats not an option either.

The best solution would probably be if its possible to create a hidden attribute that i manually check in the admin-backend for vendors that offer their services in any location, and if there is or could be a code snippet that checks on all searches if that hidden attribute is positive, and then includes those listings no matter what location is inputted in the search. That way i can still use the geolocation-plugin, use a map and radius if i want in the future and the problem will still be solved.

Actually it doesnt even have to be a hidden attribute, i can let the vendors use that checkbox when they create their profile if they offer their services in serveral cities - as long as its possible to get a code snippet that includes those listings that have this attributes checked no matter what location is filled in the search.

I hope you can understand my question, im not the best at explaining!

Thanks!

BR,
Martin