FCC Rule Part 95.1705:
(b) Individual licensee responsibility. The holder of an individual license to operate GMRS stations is responsible at all times for the proper operation of the stations in compliance with all applicable rules in this part.
(d) Individual licensee duties. The holder of an individual license:
(1) Shall determine specifically which individuals, including family members, are allowed to operate (i.e.,exercise operational control over) its GMRS station(s) (seeparagraph (c) of this section);
(2) May allow any person to use (i.e., benefit from the operation of) its GMRS repeater, or alternatively, may limit the use of its GMRS repeater to specific persons;
(3) May disallow the use of its GMRS repeater by specific persons as may be necessary to carry out its responsibilities under this section.
https://www.ecfr.gov/current/title-47/chapter-I/subchapter-D/part-95/subpart-E/section-95.1705