Shared storage

Hello...looking for a shared storage recommendation.  We run 4 edit suites (Mac Pro, iMac Pro, 2 iMacs) all running Adobe CC.  We shoot almost exclusively 4k res.  We've been editing off external drives that are backed up nightly to a NAS.   The goal would be for all editors to access all media on the storage device and edit on the same project at the same time.

Apologies if this has been answered before...first time on these forums.

Thank you!!