I really enjoy going to the support group in my area. I did go to another group but it seemed to be a lot of 'my situation is worse than yours'. I've made friends with people that understand what we're going through. There's four of us with family members in the same care facility and we do watch out for our loved ones when we visit. I went on vacation for 2 weeks and got daily texts and even videos of my mom. Don't give up on finding the support group that suits what you need.
Nannybrister, kudos to you and your sister for taking care of your mother -- it's good that there are two of you to share this exhausting work. My wife have been attending Alzheimer's support group meetings for several years and have found them to be an excellent way to learn caregiving techniques and information resources, as well as for emotional support and camaraderie. And these meetings provide great opportunity for you to help other caregivers by sharing what you've learned and giving emotional support. That said, there are variations among support groups and their facilitators. Best wishes for your, your sister's and your mother's journey.
Don't give up on finding the support group that suits what you need.