Mod Note: Just a reminder to "treat others with kindness and respect."
To the OP, as others have said, personality disorder research, even when narrowed down to "only" two personality disorders, is still a pretty broad area. Many prospective students initially start finding potential mentors by reading interesting journal articles, identifying the authors of said articles and where they work, and figuring out if they take students/participate in training. I suspect you'll probably find a few hub universities where some bigger name folks are located, and then smaller universities that are a bit more scattered around. PD research isn't my area, so I can't offer any specific recommendations there.
And not to belabor the point, but the geographic limitation is going to make graduate admissions and study even more difficult than would normally be the case (e.g., at the very least, most trainees will relocate for internship; many others will relocate again for postdoc and/or work). So that may mean you'll need to branch out in your clinical/research interests, since branching out geographically is not an option; this can be a tougher sell for interviews, so you'll of course want to plan ahead for that.