Safari Searches from Other Phones Popping Up On Mac

Strange things have been happening since I upgraded to Yosemite. I'm on a family plan with my parents and sisters, and somehow, my sister's google searches are not popping up on my toolbar on my mac. I've ran multiple searches for the solution to this problem, but cannot find anything. I'm also getting all of their iMessages, and although I can turn that off, I cannot seem to find a way to stop their google searches from connecting to my mac. Can someone explain to me what is happening and how to fix this?