Ok got another idea on the matter ...

Let's think about the inverse.  You have this subtreeSelector and when you read the entry
of that objectClass with object (base) scope without any controls you can get the following

(1) a single entry with all the member attribute values injected into it
(2) multiple entries if the member attribute values exceed a certain threshold

If a management control is present then you see the entry without any of the magic going

Now perhaps we need to make the subtreeSelector an AUXILIARY objectClass so it can
be added to static groups.  Once that happens the injection is handled by the server and
clients see a static group with all it's members.

Also we will need a threshold parameter in the subtreeSelector to be used as the trigger
to switch from mode 1 to mode 2 based on the size of the result set.