In my parish, the people chosen to bring up the offertory gifts are asked to be present in the back ready to go while the collection is taken up by 2 or 3 other ushers. One usher will give out the bread to 1 person, wine to the other. The priest gets up and stands in front of the altar, and he will generally give a look to the gift presenters to make their way up the aisle then he will give the wine to the pastoral admin then he will take the bread up after he thanks the presenters. In my parish, our ushers are asked to pick at least 2 people or a family as people arrive for Mass unless there is a special occasion brought to their attention by the priest or pastoral admin like a baptism where the godparents are chosen as an example.