1. person: prepares the beginning of the service up to Barkhu
2. person: prepares Barkhu, Shma and Amida
3. person: prepares the pieces after the Amida and the kiddush
(Each of these parts could also be prepared by two persons, then you have to
talk about who is responsible for what.)
If you are enough, there could be a 4. person preparing a short drasha or
looking for an interesting text explaining the parasha, which he could read.
It could also be enough just to read the parasha and tell us, what's in it.