Adding on to Alys’ post, if I ever set up tags again (which I’m not using at the moment – I touch every goal every day, so I prefer to just see them all at once) I’ll use @zzq’s My Beeminder browser extension to search them. (If you have that set up, then you can just hit f and the name of the tag and it’ll bring up just the goals with that tag.)
I’d love to see tags get spruced up a bit though, so it’d be interesting to know if the tags sound like what you need!