Once you execute the merge, there is no link between the document that is
created that contains a "sub-doc" for each student and the original data
source.  If changes are made to the datasource, it is necessary to
re-execute the merge for those changes to be reflected in the "sub-docs".
Of course, if the individual "sub-docs" have been modified in any way, those
modifications will not appear in the new document (containing a new set of
sub-docs) is created by executing the merge.

It is probably possible to create a macro to do what you suggest, but,
without wanting in any way to sound insulting, if you had the ability to
create that macro, you probably would not ask the question.  It would not be
a simple task.

I do not know of any other method of doing this.  I would do it all in
Access.