@pannir We run into this use case all the time in Higher Education. So, we built a community SaaS connector called Identity Fusion that will handle these exact use cases plus more.
https://developer.sailpoint.com/discuss/t/identity-fusion-connector/38793
A big part of this connector is that it will become your authoritative source taking on both your student and staff sources. You will need to create a new Identity Profile (removing the others) as well pointing to the Identity Fusion connector.
When it discovers a potential match, between student and staff, it can do auto correlation or it will create a dynamic form which allows the reviewer to review and then merge the two accounts. This way your would have one single identity cube for both accounts.
As an FYI, there is an upcoming updated SaaS Identity Fusion connector with a lot more features coming very soon. Features like Fusion Reporting, individual attribute weighings and more. You can find this update in the GIT repository under development.
Let me know if you have additional questions.