1:N Relationship in rollup field and lookup field

Hi All,

I have an example case between two entities; Mentor entity and Student entity.

I like to have Student entity having a Mentor lookup field which uses N:1 relationship from Student to Mentor, so I can show whose is the mentor of a student in a form

I also like to have a view of Mentor that show the number of Students that the Mentor has using rollup field which uses 1:N relationship from Mentor to Student.

Is there a way to utilize the same 1:N relationship for both purpose (lookup and rollup)? I am hoping that when I set the mentor from the lookup on a student form, that relationship can be used to populate the student count for the mentor view.

Appreciate any possible answer.