Boardroom wrangling is set to start as moves begin to add a third bank to the Merchant and Trust Bank planned merger.The management of Merchant and the Trust Bank, already in talks to finalize a merger deal, are hoping that a third bank would put the new entity in a better position to fend off competition in an industry that is growing rather aggressively each day.Joy Business Report sources say the choice of a third bank to come in after the two have merged is between Cal Bank and First Atlantic Merchant Bank.The Social Security and National Insurance Trust, SSNIT which is believed to be behind the proposed merger is a significant shareholder in all of these banks.