We did a couple of runs with them. They seemed to enjoy themselves, but the biggest complaint was that we ran off and left them.
I honestly don't think they want to join with us. If their website is any indication, their club isn't very cohesive or active. As Pat said, we've made several invitations to meet and to do events and we don't even get the courtesy of a reply. We've never received an invitation from them. They are welcome as a group or as individuals.