Synchronizing count for two (or more similaire items )

Hi All, i have been wondering if it was possible two synchronize two items for a count.

Here is the case :

We have a person called Williams Peter A1 arrived at first is the "Centre de coûts" (Cost Center) called TestCC1 in 04/01/2024 as we can see with the Date d'import. But along the way, he changed the cost center to TestCC2 the 10/04/2024. In our model, we know it's the same person, but a change in the status is caracterized by the adding a new item the our list, (through import) which lead to a Peter Williams A2

What I am trying to achieve is with the Headcount, what i try to do is : Putting the headcount to 1 from Jan24 to Apr24 for Peter Williams A1, then to stop the count and start the Headcount of Peter Williams A2, since it's the same person.

I Have tried by using a firstoccurence but doesn't seem to make the result, any ideas,

Thank you very much

Answers