//echo -tag . $server(#,group).pass
#=0 will tell you how many servers are in that group
#=1 first server in the group, #=2 is second, etc.
group = name of group of the servers
You really only need to use the group option if you have a situation where the same server address is used in more than one group. If you know the server address and you only use it in one group, then use this:
//echo -tag . $server(serveraddress).pass