Also if you want to do it with something that has more than one attribute (such as eyes that change expressions), then you just have to do this for each attribute.
group eyes:
auto
attribute neutral default:
"brianne_eyes_neutral_[eyecolor]"
attribute angry:
"brianne_eyes_angry_[eyecolor]"
attribute sad:
"brianne_eyes_sad_[eyecolor]"
attribute surprise:
"brianne_eyes_surprise_[eyecolor]"
attribute irritated:
"brianne_eyes_irritated_[eyecolor]"
attribute flirt:
"brianne_eyes_flirt_[eyecolor]"