I have a large spreadsheet used for attendance tracking at work. We have set
up conditional formatting so that for Tardy (T), Unexcused Absence (U) and
Unexcused Early Leave (UE), when the applicable letter is typed the cell it
turns red. We also have a tally section at the end that keeps track of how
many of these factors the individual employee has. I need to add other
formats, but there is only room for 3 custom formats. Is there a way to set
up other formulas that work in the same way where the cell changes color when
the applicable letter is typed?

If there is no way to do this, is there a way to nest some of them, such as
the three I specifically mentioned? I have tried and while the tally works
at the end of the spreadsheet, the cells do not change color. The color
change makes for a quick visual picture of the office attendance as a whole,
so it is really helpful.