Conditional Formatting - Highlighting dates in relation to dates in previous columns

Hi all

Please bear with me as this is my first EVER post on any forum!!

I am trying to formulate a "Sickness Trigger" sheet, so that it highlights dates if my staff members hit any of my company's disciplinary sickness triggers. (Triggers are on attached sheet.)

So if I can explain, all the staff names will be in column A in my sheet, their 1st period of sickness in column B. 2nd Period in C 3rd In D etc.

For the attached example, I need any date in column B that is less than 90 days since the date in column A to highlight a colour. I then need any date in column c to highlight one colour if its less than 3 months than the previous date AND if it is hitting 3 occasions in a rolling year, and so on. My sheet has 6 columns for dates.

I have tried using conditional formatting where you can add more than one argument for cells, but my brain wont work!

It's probably very simple but i cant get my head around it!

Any help would be very much appreciated!!

In the attached copy of the file:
1st trigger is highlighted in yellow using: =AND(B2<>"",B2<=DATE(YEAR(A2),MONTH(A2)+3,DAY(A2)))
2nd trigger is highlighted in amber:
For column C the rule is: =AND(C2<>"",C2<=DATE(YEAR(B2),MONTH(B2)+3,DAY(B2)),C2<=DATE(YEAR(A2)+1,MONTH(A2),DAY(A2)))
For column D the rule is: =AND(D2<>"",D2<=DATE(YEAR(C2),MONTH(C2)+3,DAY(C2)),D2<=DATE(YEAR(A2)+1,MONTH(A2),DAY(A2)))
Please include more data in order to see an application of the Last trigger which should be applied to column F: =AND(F2<>"",F2<=DATE(YEAR(A2)+2,MONTH(A2),DAY(A2)))
Let us know if you have any questions.