Mormons Building Bridges is not a formal organization and there are no formal members. Any Mormon who believes that LGBTQI/SSA people deserve to be loved and belong is a Mormon build bridges. These faithful Latter-day Saints are united only by this belief and a shared code of ethics for how to enact that belief.
The MBB Facebook group, MBB Contemplative Retreats, and uses of the MBB logo are guided by a group of motivated Latter-day Saints who come together to form an ad hoc steering committee. They are not paid and do not own any legal title or rights to the MBB moniker.