Is DEF a sorority that any of your daughters has joined? If so, maybe have her ask D if she went through AI since she had heard that she was a member of her sorority. If she says no, she can then ask why people are mistakenly thinking D is a member of DEF. If not, you could ask her the same way. Maybe she did AI DEF, and she just didn't tell you ( unless, of course, it's not a group that does that sort of thing, but she may not know that
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