Are you supposed to salute when in a group?

a. In Formation. Individuals in formation do not salute or return salutes except at the command Present, ARMS. The individual in charge salutes and acknowledges salutes for the entire formation. Commanders of organizations or detachments that are not a part of a larger formation salute officers of higher grade by bringing the organization or detachment to attention before saluting. When in the field under battle or simulated battle conditions, the organization or detachment is not brought to attention. An individual in formation at ease or at rest comes to attention when addressed by an officer.

b. Not in Formation. On the approach of an officer, a group of individuals not in formation is called to attention by the first person noticing the officer, and all come sharply to attention and salute. Individuals participating in games, and members of work details, do not salute. The individual in charge of a work detail, if not actively engaged, salutes and acknowledges salutes for the entire detail. A unit resting alongside a road does not come to attention upon the approach of an officer; however, if the officer addresses an individual (or group), the individual (or group) comes to attention and remains at attention (unless otherwise ordered) until the termination of the conversation, at which time the individual (or group) salutes the officer.

I remember being instructed that only the highest ranking individual within a group should be in charge of the salute while all others remain at the position of attention.

While in formation, except when ordered "Present Arms", only the designated leader (commanders, platoon leaders, squad leaders, etc) should salute. When marching, only the designated leader salutes, while the formation looks to the right when ordered "Eyes Right". When approached by an officer and you are alone, you are required to salute.