Unauthorized Tennants eviction

[Angela Short]

We have a couple with 3 kids under the age of 13 renting from us (all listed on the lease) in a 2 bedroom 1 1/2 bath with a very small den (no closet, not even much room for a bed). We found out that they are fixing up the small den as a room to house the wife's adult daughter and her 2 children. That's 8 occupants in a condo with 1 1/2 baths which already has water issues that the township is addressing . We feel this is will put excessive wear and tear on the home. It's in a high demand area and would be very to easy to find new tennants if this would constitute as a broken lease? Can this be grounds for eviction? Local codes and HOA do not have restrictions to number of occupants in Bylaws.