Form for email sign-up: map checkboxes to email groups and make redirect link open in new window

I have a form for email sign-up to my mailchimp email list which has multiple “segments” or groups. I would like for there to be a way to map checkbox options to email list groups and for the form to allow multiple email groups to be selected and subscribed to at once. This would allow the user to be able to select more than 1 email group to subscribe to using checkboxes.

I would also love a simple way to set the redirect link to open in a new window.

Thanks!