ACTION: First, say in DRAWING C that I create GROUP B and make it a RIGID SET. Secondly, I imbed BLOCK A in GROUP B using CONNECT relationships. Than I make a new GROUP A-1 to include both BLOCK B and GROUP A. Next, I execute a BLOCK REPLACE command from the LIBRARY of DRAWING C to globally replace all BLOCK A’s in DRAWING C with BLOCK X from DRAWING X.
PROBLEM: Any CONNECT relationships that I created for BLOCK A in GROUP B/B-1 vanish. Is there a way to maintain these relationships?
It really doesn't have anything to do with grouping. When you connect a block to geometry that is part of a group, it does not embed the block in the group. It connects the block to the geometry. Think of replace block as delete and place again. When you delete geometry (the original block), the relationships are lost.