Creating Variable stanines

I am a real newbie at this so treat me kindly. I want to be able to enter a child's score in a spreadsheet and get a stanine. I have written the formula and it works okay. Problem is, there are 6 different year levels sitting the test and within each year level, there are three stanine variations depending on whether the child sat the test in Feb-May, June-Aug, Sept-Nov. Within my limited abilities, is this possible and in simple words I can understand, how can I do it?
Thanks for any ideas or pointers