create new servicegroup and user for login to nagios core

[baber]

I want to create new servicegroup . currently I have two service group :

define servicegroup {
servicegroup_name TT
alias TT Group
}

define servicegroup {
servicegroup_name SS
alias SS Group
}


I add follow :

define servicegroup {
servicegroup_name GG
alias GG Group
}

now my current .cfg file is such as follow that assigned to TT group

define service{
use local-service
host_name mob
service_description Mob port
servicegroups TT
check_command check_nrpe!check_port!
}

1- Do I have to change it as follow if want also GG group can show it ?

define service{
use local-service
host_name mob
service_description Mob port
servicegroups TT
servicegroups GG
check_command check_nrpe!check_port!
}

2- How can create a user on nagios that can see follow service ?
define service{
use local-service
host_name mob
service_description Mob port
servicegroups TT
servicegroups GG
check_command check_nrpe!check_port!
}