Hit a wall with aggregate function

[MZING81]

I've built a tool to help me process employee vacations requests.

The formula works below, it extracts the employee's seniority/rank, for the individual week(s) in order of seniority. But I want to add in preferences.
Say employee #1 wants Week #10,Week #12 and Week #13 on the calendar, with other employees selecting different weeks in a different order of preferences.
for Week #10 you'll have all the employees that selected that week and it'll the formula will list it in order of seniority. What I want it also do is to incorporate preferences.
And they're only allocated a max of 4 weeks receive in order of preference. I want the formula to ignore any of their selections that go beyond the 4 weeks.

=IF(ROWS(C$4:C4)>C$2,"",INDEX('WEEKS-REFERENCE'!$C$3:$C$22,AGGREGATE(15,6,(ROW('WEEKS-REFERENCE'!$C$3:$Q$22)-ROW('WEEKS-REFERENCE'!$C$3)+1)/('WEEKS-CLEANED'!$C$3:$Q$22=FINAL!C$3),ROWS($C$4:C4))))

Unfortunately the version of excel on my personal laptop doesn't handle Aggregates, but the other work machine does.

Any assistance is greatly appreciated.