When premises are leased to more than one person, ordinarily all the people are listed on one lease agreement and are considered jointly and severally liable for the terms of the agreement. This means that each person is fully responsible for the entire rent. How the roommates chose to divide it up among themselves if up to them. But if any one person fails to pay their share, the landlord can come after any of the tenants or all of them for the entire rent. If the rent is not paid, all the tenants can be evicted, regardless of who did not pay their share.
If any roommate is causing problems for the other tenants, such as creating a noise disturbance or otherwise interfering with the quiet enjoyment of the premises, they may need to be evicted after proper written notice. This could be done by the landlord or, if it is a sub-lease situation, if may need to be done by the other tenants. Other civil and criminal remedies may also be available, depending on the nature of the behavior.