While I was in the military there were strict rules on fraternization not just between officers and enlisted but also between junior and senior personnel in their respective pay scales. But that was the military.

The implications of such a "rule" being enacted by a civilian firm seem far reaching, for the good or bad. As noted earlier, not even Fire Departments (or police agencies) can control whom their employees associate with after hours.

I would be most interested to hear how you fare should you seek the legal advice you most desperately need.