How do I prevent Zammad from creating a new user when an e-mail arrives?

Hi everyone,

maybe I missed the whole thing, but I hope you can help me.

Initial situation:
Zammad as SPOC, so emails arrive from various contact addresses, including kontakt@domain.de or vertrieb@domain.de
Since these addresses are also on our website, requests come in accordingly, which are not automatically customers.

It would therefore be desirable if a user were not automatically created.

Is there a way to set this up?

Thank you for your help