Sisters intertwined

I went to Australia and met two people who work on different projects at a big American company, but spend time working with other stuff they're passionate about. Two years later, one sister who went to my uni in the US reached out to me because one of my professors told her I might be able to help her on a project that combines two disciplines not many in my field are familiar with. We have dinner together and she has her husband and daughter join. she wants me to join a project with one of the people I met in Australia. And we chat, I mention I'm going to Mexico City in a couple weeks. Her daughter mentions she has a cousin there who might be able to show me around, so I hit her up. About a year later, the other sister (sister to the aforemented sister) emails me about a very different different project because the same professor told her I might be able to help (sister 2 also did her PhD at my university a long time ago). She says she's working with the OTHER person from Australia on a project. Turns out neither sister knew the other had contacted me, and I didn't connect the dots that the person I met in Mexico City was the second sister's daughter. Two sisters hit me up through the same professor vabout projects with people I met in Australia, and I met one's daughter in Mexico through the other's daughter in the US.