Most tenancy agreements (especially student ones) are joint and several which basically means you sign the agreement as a group and are all responsible jointly for the liabilities explained in the contract. For example; if there is damage to the property the landlord can hold you all liable; the landlord is also able to hold any one of you as being liable for the damage. It also means that if the landlord is required to give you notice of anything they are only legally required to inform one of you.