We have an ad out for our apartment rental and have not yet received any applications, but now have an unforseen applicant situation that we'd like to skirt around if possible.

Our applicants are a boyfriend and girlfriend, one attends the local college. Neither have any income (assuming at this point) and the boy's grandfather is offering to be a guarantor on the lease. Over the past few years we have always qualified applicants by requiring 3x the monthly rent of employment income and that has always worked well. We haven't posted those requirements but that's how we've operated internally.

Now we want to deny this applicant (or discourage them from applying) even though the guarantor would meet the minimum income requirements. Is it as simple as just stating that the kids don't meet our requirements? We've always kind of assumed the the income requirement meant that the people living there had to be employed.. so it's not like we're being inconsistent. But the guarantor complicates things. We'd just strongly prefer to have responsible adults who can actually afford to live in our apartment instead of college students. But I'm not sure if we are allowed to discriminate on this basis. Thoughts from other PA landlords?

EDIT: Also complicating matters potentially is that we were not up front with them about this (unintentionally so).. but after the mother told us this was for her kid, we still offered to show them the place, which they did end up touring. Only now after thinking it through some more are we realizing we don't want to deal with guarantors and unemployed tenants. They haven't applied yet but I'm pretty sure they will ask for an application shortly.