[KappaKittyCat]

Please do be fair and mention the other sororities. Your job is to make these students as prepared as possible to jump right in and be involved on campus, so please be sure that you explain both NPC and non-NPC options to your orientation groups. As for doing so tactfully, I imagine that you'll likely be asked what you do for fun and how you socialize, which is a great way to bring up the Greek system. You can talk about how involved it's made you on campus, mention the different types of organizations and recruitment processes, and segue that nicely into a "here's how to sign up" type pitch. That's my best advice.

If I were leading an orientation or touring group around my campus, I might say, "Here's the Library. Students gather here to study both alone and in groups. The first floor is generally a little more crowded and geared toward group study than the other floors, but my sorority usually manages to find a quieter spot in the corner to have our study table."

Get it? These new students are looking for examples of what life is like on campus, and they've got you: a real, live, example of what life is like on campus. When you show them around, offer a personal touch, such as what friends of yours or you personally do there, and mention your GLO as much as you can (without sounding like a scary brainwashed cult person, y'know what I mean).

Best of luck to you. I'm sure you'll put in some great plugs for the Greek system.