these are almost always rented if the organization did not buy and hold it in score library
ie
https://www.musicsalesclassical.com/rental
also the publisher webs for Hal Leonard, Schirmer, etc can be contacted to ask for quotes from the sales people in rentals depts
First, I am going to be rather harsh because those who post as "Visitor" are University Piano Faculty who would have a Senior Diaper Incident if there actual names were ever revealed. To date, I have NEVER been personally trolled by using my real name in my posts.
GROW UP!
Next, as referenced in another post, "Music Minus One," is a bad joke. If you (or anyone else) does not have an audio technician to adjust ("at will") the tempo of any particular passage of any Piano Concerto when one needs to ("Stop and Start"), then it is useless.
Believe it or not, according to Earl Wild's Memoir, in the old days the Conductor on any particular recording project would get the (usually BBC Studio) to record everything in separate parts, and then piece it together.