calculating minutes and seconds 4 ways

[Eris52]

I am new to Access, and I cannot seem to get the solution to these
issues:

I have 6 departments (A, B, C, D, E and F). Dept. A is alloted an
aggregate total of 1 hour per month for specific projects that are
calculated in minutes and seconds; Depts. B through F are alloted an
aggregate total of 3 hours per month for specific projects that are
calculated in minutes and seconds. I need to know how to program
fields on the input form that allow the users to:
1) select their specific department from a drop-down list
2) allow the user to input the minutes and seconds for one of their
specific projects

and then for my use there should be fields on the form that display:
3) Aggregate total Department A time in hours, minutes and seconds for
the calendar month
4) Aggregate total Departments B through F time in hours, minutes and
seconds for the calendar month, and
5) Aggregate total all Departments time in hours, minutes and seconds
for the calendar month.

I have tried a number of DSum variants (and more), but even after
buying and reading two books on Access, I can't seem to resolve the
field issues - Please help!