Create the aura with whatever icon you like. You will need two triggers. One will be checking the buff "Well Fed". Then choose the check box to invert it so the icon shows when the buff is missing. Do the same for the name of the flask buff you want to check on the second trigger. Then I believe you will need to change the load options to get it to load only when in dungeons/raids to have it only show in groups.
"he doens't need healing, he doesn't need healing, he doesn't nee-WHAOSHIT!wtf was that man!". Please stop leaning on TDR. -Teng