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What is the best practice in organizing users in the following case :

A linux system will be used for a school.
There are students in IT, Math and Physics sections.
For each section there are 4 years of studies  : 1st year, 2nd year,
3rd year, 4th year.
Some programs can be used only by students in 2nd year, or only by
students in physics, etc.

I want to assign permissions on groups to these programs.

I want to add users into the following groups :

it_year1, it_year2, it_year3, it_year4,
math_year1, math_year2, math_year3, math_year4,
phys_year1, phys_year2, phys_year3, phys_year4.

and then create groups for each section and each year :

it_students, physics_students, math_students,
year1, year2, year3, year4.

The problem is that in linux it is not possible to add a group in
another group :
it_year1 is part of year1 and it_students.

A possible solution would be to add users directly into each group but
that
will not make user administration easy. It is by far easier to add a
user in one group and make him inherit
automatically other group membership than by adding a user in several
groups, with the risk of forgetting one.

So what is the best solution to this user/group management problem in
linux ?

Thanks in advance