This was suggested in question #71554 (https://answers.launchpad.net/inkscape/+question/71554) and is related to (wishlist) #170714 "hold font size constant when resizing group" (https://bugs.launchpad.net/bugs/170714).
The idea is that a group can be set such that its bounding dimensions are changed without altering the size of teh individual objects within the group. This can be simulated for a group of same sized elements by taking one of your shapes and copying it to the clipboard. Then select all the shapes and expand, you now have the separation you want just that the shapes are larger too, now (with the individual shapes still selected) use Edit > Paste Size > Paste Size Separately.
The feature could be an on/off switch similar to the keep line thickness switch. If it also applied to text objects within a group then a group could be expanded and the text size (and size of other objects) kept the same.
Ok, I think I understood your idea. It's like scaling groups changing only the position but not the individual size, right? Could you elaborate a bit more? try to detail how would you like to access this tool. Mockup your desired workflow. This could be a propriety set on a per object basis, so a group could be composed of normal objects and "fixed" objects.