Is your group a school? I think a good first step would be to speak with the building manager and find out whether they have worked with a scaffolding company in recent months or years. First, it is a good way to find someone that your group has a track record with -- assuming they were reliable. Second, if they were used before, then they must be an approved vendor, something that some schools are very strict about--paying outside vendors, making sure they meet the various criteria, etc. If you know what you are looking for, I would think that any scaffolding company would be able to accommodate your needs--those elements are very versatile and can be made into most configurations--like the erector sets we played with as kids. Good luck.