[SWTXBelle]

Back to the op - I would look at it in the same respect as in dealing with distant family members. In true southern style, my family is spread far and wide, and we all know our genealogy. They are family, but that doesn't mean I would contact my second-cousin once removed and ask to be put up for the weekend. I would feel comfortable contacting a distant family member, saying I would be in the neighborhood and would like to meet them over lunch or dinner.
Same for my sorority sisters. I always feel a bond with my sisters whom I've meet from far and wide. If I were an active and some sisters called about visiting, I'd love to meet them - but without knowing them wouldn't commit to a weekend or to putting them up in the house. So - my take on it is if fraternity brothers from XYZ want to visit, I'd suggest they come visit the house for a tour, maybe tell them where the brothers meet on Friday night and offer to help them find a hotel to stay in. That would be enough hospitality, imho. If you are having an event like a football or basketball game they could attend with you, great.