Macro for duplicate rows with conditional formatting (updated).

Hello there!

Running a science project and I've stumbled across some huge issues with duplicate rows.

The issue as follows:
I've got a dataset with around 3000 rows with different duplicate ID:s.
The first row for every set of duplicates is the first event based on column O "Event_date".
Based on the column H "Side" i'd like to delete forthcoming rows with the same ID
that does not match the side of the first event row.

I've attached an excel file with the issue and given some more examples of my problem.

Sorry about my lack of skills in trying to explain my problem and also in excel...

Thank you for the help!

It would be more understandable if you only indicated what you want to delete. For instance, the first item in your example indicates that you want to keep the data. It leaves the question of the Primary entry's status of keep or delete.

Edit this and add to it if more than three events. Only indicate what you want deleted.
If 2 duplicates and the secondary event is on side 2 delete.
If 2 duplicates and the secondary event is on the same side, do not delete either.
If 3 duplicates then delete the earlier of the side with two events.