I posted a similar request in the InDesign Uservoice but it would be great that instead of copying the files over when adding/dragging in a InDesign IDMS file from Libraries it is linked to that file. It would be useful when using a IDMS file (say an ad) that appears in several InDesign layouts but gets updated on a regular basis so it does not have to be re added each time but simply updates like a regular link. Maybe there could be an option to Embed/Break link if you don't want to update the placed IDMS file within a specific document when the IDMS file is updated.