I went here with a 4 of my friends, at the end of ...

I went here with a 4 of my friends, at the end of our meal there was an 18% gratuity added to each of our checks, I ask them to take if off and I was told they couldn't the register did that, but there were others at our table not in our party that did not have the gratuity. I told them I was paying for me and my daughter, they brought separate checks with the 18% added to both. Last I checked the gratuity was added to parties of 6 or more and the gratuity can be taken off, because you cannot be forced to pay for bad service. I visit restaurants all the time and I tip very well, but this place will not get anymore of my business. Management didn't even take the time to come over and address the issue