[Kevin]

I'd do everything Beta said (all great advice). To that, I'd add that I'd make sure that my own organization would remain on top (if I were in your shoes) in order to do so, I'd look for the most dynamic leaders on campus and recruit the hell out of them. Don't wait for whoever goes through rush, go out there and find the best guys for your chapter. If you can, try and get members elected to all of the major Campus Activity Board offices, student government, etc.

If the Greek organizations start to take over, people who want to 'be involved' will see Greek Life as something that is more of a necessity than a side trip.