M-x grep command is very useful in a number of situation, because, for example, it give you direct access to all matched file ...
But there is not so intuitive how to use grep when opening file via ssh, this is the trick:
First generate a key pair and upload public part to the remote server:
(suppose remote host/user is B/b)
ssh-keygen -t rsa #... ssh b@B mkdir -p .ssh cat ~/.ssh/id_rsa.pub | ssh b@B 'cat >> .ssh/authorized_keys' ssh-add
be sure to use ssh-agent in order to use ssh-add