the resteem option is already included in the system of the group because people there are resteeming each other and the moderator controling it.
You have just to upvote 3 post from users who pay 0.1, and 1 who paid 0.5 and resteem updates about the group when I write them.
In fact you don't have to resteem people but if you will support the group you will be rewarded, I think I will add that the next month like an obligation.
Anyway for more details contact me here : Senouci Bouabdallah.