You can merge several customer lists into one from the customer list view. The exact process is shown in the following video.
Once you have pressed the merge button, you can choose which account you want to merge from the overview. You can decide this, for example, based on the customer number that is to be retained at the end.
In the next field you can then decide which addresses should be transferred and which of the addresses should be the standard address.
In the third and last field you can decide which telephone numbers and e-mail addresses are to be transferred.