You actually answered my question, thanks. I was/am just curious about which person has the decision power about who works on which part. But I guess it goes so

You actually answered my question, thanks. I was/am just curious about which person has the decision power about who works on which part. But I guess it goes something like: person A tries to solve X. If he can't solve it, he asks the team and someone in the team will try helping. If the problem cannot be solved within a reasonable timeframe, then someday management will ask what's going on.