J.S.
You don't have to do anything. You don't say how far along you are but from your profile, it looks like you're 8-9 weeks? Congrats! Anyway, someone will offer to host one and will get the ball rolling when you're about 6 months along. The actual shower will be about a month before you're due, assuming that you don't have to travel or have complications or other factors that would make something earlier make sense. You let whoever wants to host something for you do all of the planning, and give her input if/when she asks.
As the months move along and the ball gets rolling on planning, I would seriously re-think the idea of having 5 showers. I can't imagine a family scenario where that would be necessary - and I come from a complicated family - but more to the point, you are going to be EXHAUSTED. There's no way someone in her 3rd trimester can be a gracious, grateful guest of honor at five different events. So although you can't be involved in the planning or pick a hostess, you may want to plant the seed that not every warring faction gets to host a separate event and some of the guest lists will just have to be consolidated and people can decide on their own whether or not to come.