This question deals with pouring the wine into one chalice instead of many individual small cups for the congregants to consume. In my experience, I've observed that the wine is always poured into a single chalice, never into individual cups. Is it to conserve resources, or is there a theological reason behind this practice?
The practice is entirely biblical. At the Last Supper, Christ took a single cup at the end of the meal and handed it round the apostles:
The General Instruction of the Roman Missal has this:
A related question is why there tend to be individual wafers rather than a single large bread roll or loaf which is divided amongst the congregation. This is because of its change of substance: “This is my body,” which means that any crumbs must be dealt with. Tearing or cutting a loaf, while a valid symbol of the distribution, would create so many crumbs that it would be impossible to deal with. A wafer with sealed edges produces far fewer problems. Generally the wafers are consecrated in and distributed from a single vessel [ciborium].
It’s a related question because of the risk of spillage in distributing the sacrament in — and between — small individual cups. A large chalice has to be carefully handled, and the risk of spilling the sacrament is likely to be reduced. However this is incidental to the primary reason: Jesus used a single cup.