25 CFR § 582.5 - How does an entity other than a tribe request to participate on a limited basis?
(a) An individual, whether acting on his or her own behalf or as an agent of an entity, or an entity other than the tribe identified in § 582.2, may request to participate in an appeal of an ordinance disapproval on a limited basis by filing a submission with the Commission within 10 days of the filing of the notice of appeal.
(b) The submission may contain supporting documentation, and shall state:
(1) The individual's or entity's property, financial, or other interest at stake in the proceeding; and
(c) The submission shall be served concurrently on the tribe consistent with § 580.4 of this subchapter. Failure to properly serve the tribe may be a basis for denying limited participation.
(d) Within 10 days after service of the submission, any party to the appeal may file a brief and supporting material in response to the submission.
(e) Within 10 days of the filing of a response pursuant to paragraph (d) of this section, the Commission will notify the submitter in writing of its decision whether to accept and consider the submission and will state the basis for its decision, which it shall serve on the individual or entity and the tribe.