Although not the same time as this new accuser, I attended Gaithersburg High 88-89, went to many large parties in the general area for years, and never heard anyone say anything about 'gang rapes' going on. Hard to believe that it wouldn't have at least been rumored activity.
I had older friends who would have been at Gaithersburg as well, but probably not as far back as when she was there. Haven't talked to any of them for probably 20 years. Just texted one friend from the area, but he went to a different school. All but guaranteed he never heard of any 'gang rape' parties either.