collect email as contact person

Hello,

in the output management we defined that the system have to decide if the output channel is eMail or Print. When the Customer have a contact person, than the Billig document will send via eMail, otherwise as print out. Now we have some big customer wich have an collect email like "rechnung@abc.de". Now we have to avoid, that we create an anonymous contact person. How can we solve this issue? Did someone face a similar problem?

Thanks a lot ans best regards

Michael