As is, as new files are added to folders that are already indexed by IMatch, the database will in turn, automatically update itself. However, if something outside of IMatch 1st, creates a new subfolder that isn't already in IMatch, and then, 2nd, adds a file to that newly created folder, IMatch won't recognize it, unless I manually rescan. Is there any way to have the program automatically acknowledge this activity and act accordingly?
This behavior is by design.
IMatch will not automatically add sub-folders you create elsewhere. IMatch brings them in when you manually rescan the parent folder.
This allows users to control better which folders they want to manage in their database. Very important.
You can change this behavior under Edit > Preferences > Indexing. See the corresponding help.