Please help me find a film from the 60's/early70's

[ed43b]

Hi I've been looking for this movie I saw a while ago set in America on the West Coast (California or somewhere like that) in the late 60's or early 70's and was made around then as well. I don't really remember the plot, just a few details:

-There are a few scenes of lavish, debauched parties with movie stars, hippies, lsd etc. and I remember an instance where a wealthy old man, out of place at a lavish mansion party, is persuaded by hippies to get into their hot-tub (quite funny). At this same party he catches his younger wife with another man.
-There is a small party at a beach house that ends with an eccentrically dressed transvestite shooting a guest and then going on a rampage
-The lead male character is a bit of a playboy and he falls for his employer's fiancee, the film ends with him driving a 60's red muscle car to her house as she leaves to catch a flight but she goes anyway and leaves him basically crying on a hill.
-The main character's employer was a bit of a mafioso and pays him a visit with his goons in one of the last scenes while the main character is sat watching Nixon having a presidential debate on the televison.

This is all I can really remember of it. Sorry its a bit garbled and I've probably made the movie sound worse than it is but I couldn't find anything on search engines and I would really appreciate it if someone could help me!

[Anomaly]

Sorry its a bit garbled and I've probably made the movie sound worse than it is but I couldn't find anything on search engines and I would really appreciate it if someone could help me!

Actually sounds pretty entertaining from what you said.

[astrakhan]

Not sure about all the elements you mentioned but could it be Serial (1980)? Sounds like a good laugh anyway.