Multiple Deacons at Mass
Priests, deacons, and laity all have appropriate roles to play in the celebration of the Mass. The involvement of lay persons in the Mass should be encouraged as appropriate. Therefore, deacons should never take over roles that belong to the laity, such as serving as reader, cantor, usher, or altar server, when lay persons are available to fill such roles.At the same time, lay persons are not to assume the role of extraordinary ministers of Holy Communion, except when and where there are insufficient numbers of ordinary ministers (i.e., bishops, priests, and deacons) to distribute Communion at Mass.
As a general rule, only those deacons should vest who have a legitimate diaconal role in the Mass. With the exception of major parish or archdiocesan feasts celebrated by the Archbishop, no more than two deacons should assist at a Sunday or daily Mass in the Archdiocese of Kansas City in Kansas.
In keeping with liturgical principles expressed in GIRM 109, on those occasions when two deacons are present, they may both exercise diaconal roles at Mass. On such occasions, the duties are split between a Deacon of the Word and a Deacon of the Eucharist.
Ordinarily, the Deacon of the Word executes the roles of the deacon from the Introductory Rites up to and including the Universal Prayer, while the Deacon of the Eucharist executes the roles of the deacon during the Liturgy of the Eucharist (though both deacons would assist with the distribution of Communion as ordinary ministers) and the Concluding Rites. For pastoral reasons, however, the roles may be divided differently.