how to disolve a group?

i have created a group with a friend and now have broken up i am tha owner off the land bacause i paid for it and im payiny the mounthly fees but i gave him the owership off the grupe. I would like to know how i can get the ownership off the land back and break up the groupe

You get land ownership back from a group by selling the land to yourself. Unfortunately, if you don't have the group privilege of setting land for sale (if you're just an ordinary group member rathar than an officer or other role with special privileges), there is nothing you can do without the consent of the group owner.

As for dissolving the group; there is no way to make it happen by force. Groups automatically disband if they drop down to one or no members. If you're the owner or have the appropriate group privileges, you can eject everybody else and then leave the group yourself.