It would be good to be able to select a random control group on execution of an email (as part of a program and not as part of a program) based on number or %. This group would not be sent the email/sms but would be identified as the control group against that send.

The purpose being to enable comparison on uptake performance against 'do nothing'. For example, Email A generated a 123% increase or resulted in ABC Sales.

The key is to be able to identify them based on an execution they were selected for but did not use