I have a band - let's call us "The Dirty Dogs" who has been around since 2008. We have an album for sale on iTunes, etc. There is newer band in another state who goes by "Dirty Dogs" and is preparing to record an album. They sometimes informally refer to themselves as "The Dirty Dogs." I fear that this will cause confusion among people who might be looking for us. If I trademark "The Dirty Dogs" can I force them to stop using their name? Or do I also have to trademark "Dirty Dogs?" Or is there another way to stop them from using the name?