separate applications or single login with groups

I am re-designing our student tracking system and have a design question. The main purpose of the app is for our staff and faculty to track our student's progress. These are a known group of users and currently they have their own login to our app.

We also have a need for our students to be able to view their own data. Right now we have them create their own logins using our established ID. They are typically only viewing data entered by our staff.

So here is the question. Do I keep separate applications, each with their own specific specs, or do I try and combine and use some sort of group/admin/etc. to determine what they should see? We do have faculty who are students and vice-versa.

I don't think there is a wrong answer, just looking for opinions.