Subgroup (noun)

1. A smaller group within a larger group.
2. A subset of a group of people or things that share certain characteristics.
3. A division or category within a larger grouping.

Origin:

From sub- + group, meaning "a smaller group within a larger group.".

Examples:

1. The subgroup was created to focus on specific issues.
2. The subgroup was made up of members with similar interests.
3. The subgroup was given the responsibility of developing new strategies.
4. The subgroup was analyzed to determine the effect on the overall group.
5. The subgroup had a significant impact on the outcome of the project.