whats that movie where group of 20-28 years olde friends are killing by accident some guy then...

one of the girls ( I think Lisa Kudrow)was afriad that their neighbor (nice , older lady) saw them carring the body down the stairs and she poisoned her by putting some drug i to her tea ! Then their car got towed (with the body in the trunk!)and when they went to towing company they killed the guy who worked there.Later they broke in in to some metal factory and dispsoed bodies in to a huge pot with hot,melted metal. On the end one of the girls(again I think it was Lisa Kudrow) hangs her self because cant live any longer with all this guilt of killing people. PLEASE TELL ME WHAT IS THE T

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