This is a little trick, because all commands are cleartool lsactivitylimited to one pvob ("project vob" or "special vob with UCM metadata in it"):
cleartool lsact -invob \my\pvob -stream ...
And the activity can be reused (this means that the old activity may have the latest versions in its set of changes)
If you have two source lines, you can easily distinguish them (by activity): see diffbl**.
ct diffbl -act baseline:bas1@\myPVob baseline:bas2@\myPVob
( Vob, )
, , , , .