Has the other member of the quad noticed you being slighted or shut out? Or any weird energy surrounding the topic? And would that person tell you the truth? I don't mean that in a malicious way but rather to save your feelings and preserve the group.
What about asking the quad to open up? You could go off and find a more receptive partner or partners. Why beat a dead horse. If they're in a NRE state they might not have strong objections.