Happy New Year! I hope you all had wonderful Holidays.

I am getting a 6' 4-post open rack to install 3 (maybe 4) 2U servers along
with 3 (maybe 4) 2U rack mountable APC UPSes for my newly built air
conditioned room (more like a large closet).
Should all the servers and UPSes stacked up close to each other without
leaving space in between or it does not matter? My concern is the
temperature and the air flow. I do plan on installing the UPSes all the way
at the bottom of the rack though (no space) but what about the servers?
Should the servers be close to each other but away from the UPSes or again,
it does not matter.

Thank you, as usual.