Prisoner Problem

5 prisoners are going to be executed. There is only one chance that they all are released. They have to solve the following problem:

The prisoners are separated into two teams consisting of two and three people. The two teams cannot see each other. Each prisoner gets either an "X" or an "O" on his head and he cannot see which letter he is assigned to. However, he can see which letter the other member(s) of his team have. The prisoners are not allowed to tell any other prisoner (either of the own team or of the other team) which letter they see. The distribution is "3 times X" and "2 times O". All prisoners know this ratio.

Which prisoner will find out the letter he is assigned to, if the letters are distributed in the following way?

Remark: Assume that all prisoners are intelligent and no prisoner wants to risk the prisoners' life by just randomly guessing. The prisoner have one day to solve the probelm.

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