A little more context would help make it clearer but with the growing shortage of priests in the developed world much more emphasis is being placed upon the 'mutual ministry' of laity and the priesthood. Lay members of the congregation are taking on some of the duties traditionally performed by the local parish priest. i haven't heard the term 'mutual ministry committee' but it has a similar meaning maybe to 'pastoral council' where parish finance and organisation is the reponsibility of a group of elected lay members in cooperation with the local clergy.
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