Caterpillars represent the immature (larval stage) in the life cycle of moths and butterflies. Of course, butterflies are very desirable beneficial insects and we don’t want to kill butterfly caterpillars.
Moth caterpillars are introduced to your garden when a moth lays eggs on your plant leaves. You may see these eggs on the undersides of the leaves of your plants.
Some moths lay single eggs, and others lay clusters of eggs.
Naturally, each egg hatches to become a little caterpillar and the caterpillars set to work eating the food of their choice.
Selectively donate/share one plant with them and hand remove or spray with insecticidal soap the others.