If I owned a small business or range/FFL licensed retail location, Id have SOPs & rules, RE: gun ranges, requirements and/or access control.
If suicides, fights, general misconduct(unsafe acts, horse-play, etc) were a major problem I'd be real strict.
In general, I'd require a renter(customer) have either a US military ID card, a valid concealed carry license(with clear photo), a NRA membership ID card or documented proof of NRA firearms safety training, a US Dept of Veterans Affairs ID card, a valid state DMV issued DL with a US military veterans endorsement(yes, you can
get that now, my state does it for honorable discharge veterans for $1.00,
I'd have CCTVs & DV systems monitoring the range & lines 24/07/365 too.
Any shooter or customer who refuses to comply with the range SOPs or who becomes hostile/aggressive will be subject to a formal trespass notice by the local LE agency and/or removed from the property.
I'd talk to the PD or Sheriff's office crime prevention office or community services officer & explain exactly what I want to do in these events. I'd also request a formal written policy memo or memorandum of understanding so any disputes or problems can be smoothed over.