Guardianship question?

In March of 2008 I signed guardianship of my daughter over to my in-laws. In August of 2008 my daughter came home to live with me and began attending school in our district two hours away from her grandparents. At the time I didn't see it as a issue to terminate the guardianship however just recently my mother in law decided to pull I'm the legal guardian and I have all rights to my granddaughter. I now want to terminate the guardianship legally as Emma has been living at home for the three years however my in laws are refusing to sign the waiver for no reason other than they want to see their granddaughter whenever they choose even if it means interrupting her school day. My husband their son and I also have shared custody of my son their step grandchild and our 8 month old daughter that my inlaws have only seen a handful of times. They favor our older daughter and this is the only explanation as to why they refuse to sign the waiver as they are not concerned about the other children. Will I have a hard time in court to have their guardianship terminated even though Emma has been living back at home for three years just a few months after the guardianship took place? Is this something I should hire a lawyer for? We are in Maine.