First of all, congratulations on being assertive and proactive on this issue. Showing concern for your employees' comfort and wellbeing is important. If you look at my most recent question from last week, I was in an almost mirror situation as you.
The internal employees support group is a great first start. Often having peers and management recognize such issue is the first step and a peer group could provide her the space she needs. Making management of the other members who are making such remarks aware is also very helpful. It show you being assertive and not afraid to "dodge" an uncomfortable problem. You, as a manger, have a duty to look out for your employees welfare and management on the other side have a duty to stop unprofessional behavior.
To take away from peers focus of she being solely a woman employee, having a clear company wide expectation / policy that prohibits harassment / behavior that intends to demean or intimidate others is a great step if not already in place. You want to avoid the focus of the problem being inappropriate not because she is a woman, but because abusive / harassing conduct is objectively unbecoming , no matter who the parties are.
Another solution our company recently implemented was a ethics hotline that provides the option for anonymity of the reporter. If this can be run by a external vendor, so much the better due to independence from company management.