1. This should close the Assign a Plan pop-up and navigate the user to the Plan Summary - Custom - Groups Edit screen. Refer to the specification for that screen here.
1. Check the rules mentioned in each input element. If there is an error, show inline error message, stop the check, allow the user to make changes and do not close this window.
2. If all validation checks are successful, assign the Plan to the Merchant.
3. Navigate the user back to the Plan Summary - Custom - Groups Edit screen. Refer to the specification for that screen here.