Once the form is submitted , you may extract the xml data and then
iterate the xml nodes in order to find the name of the users . Then
using the 'find user' activity, get the user info( e.g. email of the
user ) and send mail to the user list . You may find a link below for a
sample process that takes an input xml and does a lookup for the email
address corresponding to the name of the user and parallely create a
user list . finally it sends mail to the entire user list . sample:-
https://workspa...