Oh Yes, Submissive Urination - Roxy is like that too!
What I do is hold her when someone comes into the house. After a few mins. when they are settled, I put Roxy down and they my guest to not excite her to basicly ignore her, let her sniff and do her thing, and once she is calm, then people can gently approach her. It has taken 2 years, but what a difference. She went from ALL the time submissive pee to only once or twice in the past 6 months.