Ssh to role

Hi all

I need to run a command that only a role user and root can run, I need to run that command remotely by script but the roles ask for a password.

Ex. from serverA with userA to serverB with userB:
userA can ssh serverB using userB without askink for a password.
user1 es a user tha can do su to roleuser
roleuser is a role that can execute /usr/sbin/savegroup

the matter is that when I try to do tha remotely it says : su: Sorry

how can i achieve my goals

Thanks for any help