Music Lending Libraries and Copyright

A local county Music Educators Association has approached my BOCES and has asked if we would house & manage their music library. Apparently, the music library was at one point housed at this BOCES, but was then moved to one of the participating districts when BOCES said they would charge a fee for the service. It is my understanding that multiple school districts buy, share, make copies and physically loan choral and band sheet music to each other. One of the music teachers has indicated that the library consists of 581 choir pieces and that each piece has 100-200 copies (and that’s not counting the band music).

I’m concerned that the number of copies the teachers have made of each choir piece is a copyright infringement and also am unsure if it’s even legitimate to loan and share the original pieces among multiple districts for the purpose of shared usage and I’m hoping you can help point me in the right direction in terms of how a music lending library could work (legally!) in terms of copyright, licensing and fair use.