Annoying Subaru Car Alarm

I have a 1998 Subaru Legacy which thinks it is a luxury vehicle. Every time someone with a Hummer, BMW, etc. uses their keyless remote to open their car, my alarm goes off. This happens even when my alarm is not activated. My neighbor (who has a Hummer, and who set off my car every night around midnight for a month) realized she could turn my car’s alarm off by using her remote again. But most people don’t know this.

I’m tired of being told at work that someone set off my alarm again. How do I disarm the alarm without taking it in to the dealer or cutting the wire? Someone, please help!