The French Butler(1983)

The film opens with Brigitte Verbecq having sex with her husband and we see the daughter of the house talking to the maid in the kitchen. The doorbell rings and the maid answers. Gabriel Pontello is applying for the job of the butler. At first they turn him down. Then the maid is told to run after him (after being groped by the master of the house). When Pontello takes the job he has sex with all three females at their instigation and the maid and the daughter have a g/g scene.