It happened in the Main Street area just before 8pm on Monday.
The men, one armed with a hammer, went into an office and demanded money from two women, before fleeing with a sum of money and a cash box.
Police said no-one was injured but the women were left badly shaken.
The men all wore hoodies and it's believed they escaped in a dark coloured saloon car.
Anyone with more information has been asked to call the PSNI on 0845 600 8000.