are you asking for multiplayer shared storage? or for merging storage of multiple containers side-by-side to a single inventory interface, with single input/output conveyors?
-1 for the first, no vote either way for the second, as while I like the idea, by the time the tech tree advances far enough to need that kind of storage i'd assume we either have it, or we have other options with production speed and conveyor filtering / prioritizing etc.