The annexation lawsuit between Excelsior Springs and Mosby has expanded again, with a group of residents asking the court for permission to formally join the case as third-party plaintiffs.The case before the Clay County Circuit Court stems from competing annexation efforts approved by voters in both cities during the November election. Excelsior Springs and Mosby each passed measures seeking to annex portions of the same unincorporated area west of Excelsior Springs, primarily along Cameron Road and Rhodus Road. Because the approved annexation boundaries overlap, neither city may finalize annexation or exercise municipal authority over the disputed territory until a judge determines which city, if any, has legal priority under Missouri law.A motion to intervene as third-party plaintiffs was recently filed by a group of residents and property owners who live in or own land within the disputed annexation area.The motion was filed by attorney William Micha...