Reign of Kings Tournament signups

Would it be possible for a tournament sign-up plugin for people to participate?
To show a list of everyone who has signed up with a command /signedup

/Signup "sign up to current tournament"
/Signclear "Clears the list ready for next signups"
/signedup "show who has signed up"

I was looking into the GuildInfo plugin to see how they handled there listing of guild members and wether they were online but could get my attempt to work that way.

Thanks.