If an employer is a municipality, a metropolitan community, a school board, a CEGEP, or a public institution or a private institution under agreement within the meaning of the Act respecting health services and social services or the Act respecting health services and social services for Cree Native persons, and the employer undergoes an amalgamation, annexation, division, regrouping or constitution as a legal person, the new employer is deemed to be the same as the previous employer. The new employer must take into account the contributions withheld from the salary or wages paid to the employee by the previous employer.