Not all sororities operate in the manner described by JohnDGsweethrt. Some groups will sit you down and talk to you as a whole before letting you mingle, some groups will haphazardly make their rounds through the PNMs. Most sisters, if they're doing their jobs correctly, will see to it that you're introduced to as many people as possible. (And don't worry about keeping names straight. No one expects you to remember anywhere from 200 to 1500 names in a single week.)
If the sisters don't talk to you and seem more focused on chatting amongst themselves, you're going to have to decide for yourself if they're really worth bothering about.
That said, be yourself, be honest, and have fun! Learning to deal with the high energy and stress of recruitment with a smile will endear you to the sisters, and a genuine smile can help lift the spirits of weary rushers and rushees alike.
Speaking of fellow rushees, a couple things to remember: You don't have to follow the crowd who all want top-tier ABC. Be supportive of each other's choices, and it will pay off whether you join the same organization or not.
It's nice having friends in other sororities, if only as a breath of fresh air.
Good luck and best wishes!