Re: Is it ok to joke like this ....?
Peace brother Submission To Peace
I have only browsed through this thread so I can't possibly provide the fullest of advice. However, you say that she is a colleague and the other males are colleagues also.
The best way I think to reduce the problem is to call her their sister and to her, call them her brothers. Try to introduce her to them in a professional manner and subversively make them feel as though they are family to each other. Just like you treat her. In an environment that you cannot avoid you need to break the current cycle of motions which is she talks to you and they talk about her to you in her absence.
Consciously ensure that she is a sanctuary for protection by her brothers and give her the respect of a sister and get them to do the same. Try not to call her from her first name rather call her sister and encourage others to do the same.
Avoid eye contact if you are ashamed of her, but remember lowering the gaze has interesting implications to the untrained female and it may appear as though you are sending signals. Try to get her to befriend a female mahram of the male colleagues if that is possible.