I don't know how successful you would be getting high school administrators to allow GLOs to distribute information directly, but there may be another avenue.
One of the kinds of work I do for my alma mater is act as an AAV: Alumni Admissions Volunteer. We are groups of alumni who volunteer for Boston U in our home towns--manning a booth during "college night", giving presentations to HS seniors who've expressed an interest in applying, and once in a while do field interviews as part of the application process. This is not a unique thing to BU: most colleges/universities have either pros and or alumni handling these jobs.
If you could get some organized info into the hands of whoever does outreach to potential applicants, you'd achieve the same goal. You could fit it in the section under "Student Activities" or "Campus Life". Then, during "College Night", or what have you, you can introduce your GLOs and Greek life along w/ the school.
IMHO, it's a good idea. I helped staff a presentation in the fall to about 300 HS kids in the Houston area, and recently conducted an interview for an applicant. BOTH TIMES the FIRST questions I got were, "Is there a Greek system?" "Do you have a chapter of XYZ?" "Is there anything I can do now to prepare for rush?" Thank God I was up to date on our current Greek system and how it works--a lot of kids (esp in the South <g>) are really eager to hear it.
Adrienne (PNAM-2003)