Splitting spanning walls horizontally

We had a shaft wall that spanned many floors. During the DD the shaft wall was moved on each floor, in such a manner they didnt align. Changing the spanning wall to go up to only one level resulted in lot of "Rooms not defined" errors in Revit.
Fortunately the "Split" command works in the elevation too. If you split at the Floor level, the split wall gets constrained to the level too. (Splitting also keeps the wall tags intact!)