Wow... a sorority FOR engineering girls! I think that 95% of my Chi Omega chapter here are engineering majors and we have lots of fun... Although I am one of the 5% non-engineers... pesky English majors
Helpers, helpers... hmm... you said that a lot of the prior knowledge graduated, so I'm guessing it's tough to get ahold of your alumnae? Graduating doesn't mean disappearing so I'd try and snag some of those long gone people and tap into their knowledge.
If that's not an option, then I'm sure there are lots of others. But I know virtually nothing about how things are done at your school, etc (like numbers of girls that go greek, sizes of groups, etc) oh and I take it to mean that by competition you mean you lose your potential members (female engineering majors) to the other sororities?