What is an employer's pensions auto-enrolment staging date if it shares a PAYE scheme with another employer?

An employer's staging date (ie the date on which the pensions auto-enrolment duties begin to apply to the employer) is determined by the size of its PAYE scheme on 1 April 2012. If an employer shares a PAYE scheme with another employer, its staging date will be based on the total number of workers in the scheme.