MASS CHANGE KNVP without counter option / overwriting existing data

Dear all,

How can I add multiple ship-to to multiple customers without using the counter and without overwritting the existing role?

For new values, the transaction MASS/XD99 is enough but once a partner role already exists you need to fill in the counter or else the existing values will be overwritten.

How can I skip the counter in this case? Or do I need to analyze first via KNVP table to see how many counters there are for each customer per ship-to? And then in XD99 create the new values with what the counter should be per customer (adding data via import data via buffer)?

Or can we create an LSMW with an own recording, based on the questions of multiple users here in the forum, I don't think that will work.

Who can help? Thank you in advance.