Add section on importing groups of subs

doc/Language/5to6-nutshell.pod6

@@ -1560,6 +1560,30 @@ via the C<is export> role, Perl 6 automatically creates the C<EXPORT> sub in
 the correct manner for you, so one should consider very carefully whether or
 not writing one's own C<EXPORT> routine is worthwhile.
 
+=head2 Importing groups of specific functions from a module
+
+If you would like to export groups of functions from a module, you just
+need to assign names to the groups, and the rest will work automagically.
+When you specify C<is export> in a sub declaration, you are in fact adding
+this subroutine to the C<:DEFAULT> export group.  But you can add a subroutine
+to another group, or to multiple groups:
+
+=for code :skip-test
+unit module Bar;
+sub foo() is export { }                   # added by default to :DEFAULT
+sub bar() is export(:FNORBL) { }          # added to the FNORBL export group
+sub baz() is export(:DEFAULT:FNORBL) { }  # added to both
+
+So now you can use the C<Bar> module like this:
+
+=for code :skip-test
+use Bar;                     # imports foo / baz
+use Bar :FNORBL;             # imports bar / baz
+use Bar :ALL;                # imports foo / bar / baz
+
+Note that C<:ALL> is an auto-generated group that encompasses B<all>
+subroutines that have an C<is export> trait.
+
 =head1 Core modules
 
 =head3 C<Data::Dumper>