How can I have a separate email recipient per form?

The destination email of form's submission notification email is the email address in the Recipient E-mail box.

user guide: -Finding-out-E-mail-Address-used-for-submission-notifications

By changing the Recipient E-mail address for each form, the submission email will be sent to recipient email address.

Hope this answers your question. Please let us know if you need further assistance.

Thanks.

On the other hand, I might have misunderstood the question...

It could be you are trying to do this instead

user guide: -Send-Notifications-to-Multiple-Recipients

Each Notifier can have different Recipient E-mail address destination. This makes a BCC email method.

Thanks.