Suppose I add independent preparers in my organization, and they use their own PTIN to sign the return but my organization name and E-file account, am I responsible for their returns in anyway? Do their return affect me? Legally and practically?

By "practically" I mean: if they have a high percentage of returns get audited and found incorrect, would the IRS has more inclination to audit my returns? (I am not afraid to be audited, but I try to avoid the hassle).