1/ Mikhail's and Maria's / Maxim's and Olga's
2/ Maxim's/ Victor's, Sergey's and Olga's
3/ Mikhail's and Nikolay's/ Victor's, Sergey's and Maxim's
4/Mikhail's/ Nikolay's
5/Victor's, Sergey's and Olga's/ Nikolay's and Maria's
6/ Nikolay's and Mikhail's/ Victor's, Sergey's and Maxim's
7/Mikhail's and Maria's/ Sergey's, Olga's and Maxim's
8/Nikolay's and Mikhail's/ Olga's