Cedar Rapids-based First MainStreet Insurance, an affiliate of TrueNorth Cos., announced it has added three more insurance firms to its family of agencies, including two Iowa firms. FMSI has acquired Sisson and Associates of Charles City, a family-owned agency operated by partners Tom Sisson and Bob Ingram. The agency began operation in the 1940s and took over the Sisson & Associates name in 1997. FMSI also acquired the assets of Core-Vens Insurance, based in Clinton. The agency has been in business since 1963, founded by Bill Core and Ray Vens, followed by Chris and Randy Vens since the early 1990s. Also, TrueNorth’s Nashville, Tenn., branch has transitioned to the FMSI platform and will combine a book of business that FMSI acquired from Hylant Group to expand the FMSI employee benefit practice to the Nashville market.