Greensburg — MainSource Bank will open an office in Columbus in October, eventually turn it into a branch and open two more branches there within the next 24 months, said Daryl R. Tressler, chairman, president and chief executive officer. MainSource has reported assets of $2.9 billion. The move comes nearly a week after the 138-year Irwin Union Bank and Trust Co. of Columbus became the first Indiana bank to fail in the current recession. Irwin was sold Sept. 18 to First Financial Bank of Cincinnati. Tressler said by phone Friday that MainSource has hired 11 former Irwin employees and will hire about 40 more as part of its expansion into Columbus. (Star report)