Is it possible to delete 1 contact out of all lists?

Updated 8 months ago

No. Every contact is unique. Each copy in each list is separate. They might contain the same data, but they are never connected to each other.

if I have a groups column like this:
Person: A, Groups: X
Person: B, Groups: X,Y
Person: C, Groups: Y
And I import this as "MyList.csv"
This will result in two lists:
- MyList.csv X Person A Person B
- MyList.csv Y Person B Person C

Deleting Person B in list X would have no influence on Person B in list Y, because they are just two separate instances, incidentally both called “B”.