Maybe Tim will post his code....or do a search for it. I use it all the time.
;;;Tim Willey
(defun c:Xrefs2Block (/ ActDoc BlkCol LayCol Message NewBlkName ss Ent EntData BlkName
BlkRefObj XrefList dbxApp LayList ObjList FullPath NewBlk NewObjList
LayToLock XrefObj)
Gary