(a) Auxiliary services may be provided only in the following:

1. (1) Public school buildings.
2. (2) Facilities leased by the intermediate unit in accordance with the provisions of § § 17.11 and 17.15 (relating to capital subsidy and cost per square foot of leased facilities) except that no facilities shall be leased in areas excluded in paragraph (6).
3. (3) Nonpublic nonsectarian schools.
4. (4) Mobile units leased by and under the exclusive control of the intermediate units not permanently parked on areas excluded in paragraph (6).
5. (5) Demountable units, trailers, tractor trailers, quonset huts, and other prefabricated units not permanently parked, installed, or constructed on areas excluded in paragraph (6).
6. (6) Other appropriate areas, excluding churches, synagogues, or areas under the control thereof or facilities under the control of a sectarian school.