Let’s make a low level conjuration spell. Credit to my wife for the original idea!
When you finish this spell, you link two bags together, so opening one bag shows the contents of both. Only one bag may be opened at a time. Opening one causes the other to close, and both bags register as carrying the weight of all items in both bags. When a bag is forced to be closed by opening another, all items in the closing bags opening are expelled with no damage. Only items that can fit in the bag are allowed to move from one bag to another. A linked bag may only have a total volume of a quarter of a cubic yard. Placing any item that has an extra-dimensional space such as a portable hole or bag of holding acts as if a bag of holding is placed into a portable hole.
At higher levels.