the s5s, one uses the others exhaust as intake air?
yes unfortunately.
It'll be in a AC'd datacenter so should'b be a problem.
Currently in my garage (no AC)
Front S5: 51 average
Rear S5: 55 average
S7: 51 average
Note: S5 use ambiant air from the garage, S7 has a direct air intake from the outside (currently temp <10C outside)