Marine/Army frat reg?

Military: Is there an actual article in the UCMJ or Marine Corps manual restricting especial friendship between a junior enlisted Marine and Army NCO? Or is it all discretionary?

as per the ucmj fraternization is an unprofessional relationship between officer and enlisted. anything beyond that is command discretion.
keep in mind that as long as that relationship has no effect on job performance because youre not in the same shop/unit/chain its harder for them to justify calling it fraternization…
although they can call it whatever they want if they feel its unprofessional and charge one or both of you for it.
i have enlisted friends, i have officer friends.
i have no friends on the job.