If there are two or more applicants, it is sufficient for at least one of the applicants to satisfy these requirements. This also applies if a national or resident of an EPC contracting state is mentioned in the PCT request as applicant for a single PCT contracting state. However, the applicants for the national and regional designation of a PCT contracting state must be the same. In other words, the applicants for the "EP" designation of an EPC contracting state (the regional designation) and for the national designation of the same state must not be different. The same applies for any other PCT contracting state that can be designated both nationally and under a regional patent treaty. So the simplest way to proceed is to designate the applicant "for one single PCT contracting state" as applicant only for a PCT contracting state which does not belong to a regional patent treaty.