Commonality of interest
Commonality of interest. (1) Employer members of a group or association will be treated as having a commonality of interest if the standards of either paragraph (c)(1)(i) or (c)(1)(ii) of this section are met, provided these standards are not implemented in a manner that is subterfuge for discrimination as is prohibited under paragraph (d) of this section:
(i) The employers are in the same trade, industry, line of business or profession; or
(ii) Each employer has a principal place of business in the same region that does not exceed the boundaries of a single State or a metropolitan area (even if the metropolitan area includes more than one State).