Two managers at the Fourth Wall, 228 Tremont St. near Stuart Street, told the Boston Licensing Board today they're trying to buy the place from an owner who already has no fans on the board and that their priority is stopping a seeming flood of under-21 drinkers who have been flocking there with fake out-of-state IDs. "We apologize for being here this morning," Fourth Wall attorney Curt Bletzer told the board at a hearing on on incident on Feb. 13 during which two BPD licensing detectives found a table with seven women, all 19 or 20, with alcoholic beverages - and possibly could have IDed more tykes, only the tables around them quickly emptied out as they were busy examining fake licenses around the table from states west of Williamstown. The bar faces a second hearing for a similar seven-people underage violation in April.…