What should I do about this dysfunctional work environment situation?

I work as an HTML developer for a software company. There are some definite “cliques” in our company, which is normal.

However, in the programmer – designer clique, there is an interesting dynamic that has gotten a bit out of hand. There are approx. 6 of us who regularly interact socially during work. We are all within 5 years of each other age wise. We are all peers, except for our senior department manager.

There is a lot of raunchy humor, sarcasm, and picking that goes on. It took me a while to get used to it, but I finally have. My dept mgr and I are both of mixed decent. There is one other black girl, a Peruvian girl, and two white men.

The black girl – we’ll call her Sandra. Sandra is a mousy, geeky, overweight, quiet, homely looking girl. One of the white guys – “Carl”, is a programmer. He dated Sandra many years ago. She has outwardly expressed her hatred towards him in our social situations. “Carl” and I dated on and off for the past year and recently broke up, and it was friendly at first but turned sour. I have since kept my distance from the group in its entirety.

It started with what I thought was “playful” teasing from our dept mgr, “Rick”. He once punched me in the arm while we were out to lunch. Since we are both part black, he thought it would be ok to call me the “N” word. I quickly told him I was not comfortable with that. He apologized and immediately refrained from using that term with me. In contrast, he has also been like a big brother to me and has been supportive and kind in other ways. Yes, confusing.

Sandra has been known to go into states of withdrawal where she talks to no one. Then she is friendly to everyone. It is very confusing. Most recently, she has starting saying things to me and the Peruvian girl, “Lisa”. Lisa is attractive and I will humbly say I am as well. Yesterday, she called us “skanky hoochie heifers” that she “does not like”. Later that day, she told me to my face, “I hate you and I am not kidding”. “Lisa” and I are close, and she has said that this is not the first time “Sandra” has said things like that to her, but she just ignored her for a while and it went away. Nonetheless, she is an extremely talented programmer who helps our department selflessly. On a daily basis, she will drop anything she is doing to help us figure out things we cannot resolve.

Regardless, I think her most recent behavior has crossed the line, but since there is a history of acceptable dysfunctionality, I don’t know what to do or who to say anything to. My direct manager was in the office the third time “Sandra” said, “I don’t like you”. He made an attempt to speak up in response to her but it didn’t seem to matter.

My first instinct is to speak directly to “Sandra” and if that is not successful to go to the HR department.

Again, since these are all my peers and the history is that of crossing the line with crass humor, I don’t know if this will shift the entire dynamic of our group. Or maybe it needs to. We are mid-thirties, and this feels like high school behavior.

So,

1. What would you do in this situation?
2. Do you have a similar dysfunctional work environment? If so, tell your story. Did you stay, did you break the pattern, did you find another job?
3. Is there a slight chance that her apparent insecurity and jealousy are related to us dating the same guy? (I had no idea they had been an item until we were dating for a few months)

Thanks for reading my long post!