because you have some logic on your e results, based on the s criteria, it has to be solved through helper entities, with associations to s and e.
one helper entity to keep the skills selection.
one helper entity for the matching employees.
to find any e matching one of the skills, you can retrieve e with an s associated with the selectionhelper.
each e will be associated with the matching entity and a count can be calculated.
this resultset can be returned to you