Cloud storage

[With a box]

Something like Dropbox.
You put something in chest A, you can find it in all synced boxes.
How much it will cost?

[Firest Kathon]

Do you need this to store items for yourself, or also for others? If its just for yourself. Secret Chest (http://www.d20pfsrd.com/magic/all-spells/s/secret-chest) may be usable.

If you also want others to be able to access the synced chests, you may want to clarify if you want the item to be in all chests or in any chest. In the first case, you would require some way of duplicating the item, in the latter case you "only" need to transport it to the correct box.

[Deophaun]

The only RAW way I know of to do this would be through creative use of ring gates, and it would be expensive at 40,000 gp per "chest." Basically, you'd embed one half of a pair of ring gates into a container, which would allow you to reach through your end to put anything in or take anything out. Then you can embed one half of another pair in that same container, allowing two people to have remote access to the same storage space. Do it with a third, fourth, fifth, however many the chest can practically support.