how i add user in user group by using mashup?

hello,

after create user in mashup want to add that user in user group. if want to add admin, i give first name, last name, contact number, emailid, username and password after enter these fields i have click on add admin and after clicking add admin it will store in thingworx user list and add that admin to user group. please refer attachments below, first attachment is add admin mashup, 2nd attachment is thingworx user list and 3rd attachment is studio admin user group which i want to add user