Wondrous Item, very rare (requires attunement by a Two people must be near each other with both bags for at least a day for it to work and for it to be bound, or else it'll just be two regular bags of holding. )
The bag has to be attuned to another person that has another copy of the bag, attunement needs about a day until the bags are bound forever. If one breaks, the other must also, and all the items in those bags are to be lost in their plane.
Notes: Two people must be near each other with both bags for at least a day for it to work and for it to be bound, or else it'll just be two regular bags of holding. , Teleportation