You cannot register your band because it's not a person. Each author must provide their personal information on the contract. However, you can put the name of the band when you register the tracks.
But note: if all the members of your band together reach 100% of the songwriter shares and you're all registered with Soundreef, you don’t need all of you to submit the tracks.
Only one of you can do it by marking all the other members and adding their respective shares.
Each one of you'll then receive the registration document and to sign.