zsh completion for cssh: complete hosts from /etc/hosts as well as ~/.ssh/config

my zsh completion file _cssh has this line, which completes hosts only from /etc/hosts: '*:userhostport: _alternative hosts:host:_hosts usersathosts:userathost:_user_at_host' how do I make it complete hosts defined in my ~/.ssh/config, same as ssh does ? the full _ssh file is here I don't need to complete usernames. Just hostnames from /etc/hosts as well as hosts defined in ~/.ssh/config. Also, it is important that multiple hosts can be completed (cssh is cluster ssh and takes multiple hosts, unlike ssh)