100. Within a base rate area no telephone company shall connect more subscribers to any line than are contemplated under the grade of service charged the subscriber on such line. Beyond the base rate area where multi-party service is, provided, no more than eight (8) subscribers shall be connected to any company owned line. All circuits now serving a greater number of subscribers than is permitted by this rule shall change to conform to these requirements within one year from the effective date of these rules. The telephone company may regroup subscribers in such manner as may be necessary to carry out provisions of this rule, but it shall not deny service to any person now receiving service. In an emergency, up to ten (10) subscribers may be connected to one line pending the construction of additional facilities o r the obtaining of enough additional subscribers in the area to justify the construction of an additional circuit. Ten party selective ringing may be supplied outside the base rate area with the approval of the Commission.