Finish build Trigger and notifications

Suppose  you have 2 builds A and B.  And B has a Finish Build Trigger on A.    A has a VCS trigger.  Now A is kicked off by a commit and if it fails it will notify people in the change list that the build has failed.  But what happens when build B fails,  is TeamCity smart enough to know  to send notifications to the change list on A?  Or do you have to but a VCS root on B to get a change list to have the notifications work?  However, there would be a problem with this, because there could be commits after A started and before B started so the change list would not be correct.  Does adding a snapshot dependency do anything here?