A method for operating an automated storage and retrieval system includes transferring a first item storage container from an aisle to a first region of a first storage location, positioning a second item storage container in the aisle proximate the first item storage container, interlocking the second item storage container to the first item storage container by engaging a releasable coupling structure extending there between, and applying, in a first direction transverse to the aisle, a force to the second item storage container sufficient in magnitude and duration to cause the first item storage container to occupy the second region of the first storage location and the second item storage container to occupy the first region of the first storage location, whereby the first and second item storage containers remain interlocked while in the first storage location.