Bags of Transporting

These bags initially appear as a  Bag of Holding. Coming, ideally in pairs these bags work together, but function in a different and flawed manner separately due to imperfect construction.
When within 500 feet of each other a Dimension Door will transport items placed in one of the bags to the other. Each bag opens no more than to accommodate an item of one foot in its smallest dimension. Items are accessible only from the bag to which they ere transported. If the bags should be separated by more than 500 feet then items placed in either bag are simply transported 300 feet in a random direction.