Query regarding Symantec DLP 14.6

Hi,

I am a bit new to DLP so pardon the noob nature of the questions. I have following two queries related to the product:

1. We have alerts generated for specific users that we know are valid that have to send out data. For instances where we know the activity is valid, is there a way to close these incidents automatically with a comment of the known activity?

1. How to apply a policy only to a specific user group that is created. 

Thanks.