In Engpsh class, you can say "We're having a group competition" or "There's a group competition happening in class." You can also say "We're doing a group competition in class" or "We're having a competition in groups." It's also common to say "We're having a team competition" or "There's a team competition in class."

It's important to note that "group" and "team" are often used interchangeably in this context, and both can be used to refer to a small group of people working together towards a common goal.