Goldie Hawn gives a heart-breakingly brave, endearing performance, and Susan Sarandon a shrewdly withdrawn one in The Banger Sisters, but writer Bob Dolman's directorial debut betrays his stars. Two old pals -- groupies who snapped pix of the rock-star members they caressed in the '60s -- Suzette (Hawn) and Vinnie (Sarandon) were dubbed ''the banger sisters'' by, we're told, Frank Zappa (a slander on the dead, since Zappa invented a much better term for such women in ''Suzy Creamcheese''). ''Sisters'' could have explored how female counterculturalists were exploited and liberated by hippie sexual freedoms, but instead, Dolman reduces Sarandon to an uptight suburbanite and writes Hawn as a bigger bubblehead than she ever was on ''Rowan & Martin's Laugh-In.''
Sarandon handles the initial embarrassment of introducing her friend -- and by extension her past -- to her husband and children with aplomb. And you can see Hawn trying to insert some irony and grace into her lines, but her character exists to wiggle and coax Vinnie to, y'know, groove on life. In a disconnected subplot, Geoffrey Rush gives an understandably panicky performance as a blocked writer whose creative juices flow only after Hawn's strenuous ministrations. Really, the sole favor Dolman does the plucky Hawn is to light her rear end so that its continued gloriousness can be appreciated.