I guess this was asked earlier here Align (Center) based on only one item of a multi-item group? - but I couldn't really see a solution; so I'll try again:
Consider this situation - the reddish objects are part of a group:
I would like to align the selected red rectangle (the child in the group) left with the grey rectangle - and move the enclosing group correspondingly.
Of course, in the above situation, I can do Ctrl+Shift+LeftClick of the gray rectangle, and click on Left Align - but that will just move the red rectangle child, and will leave the other group members in place.
Any way to do this easily in Inkscape?