This Condition located on the Miscellaneous category tab in Search Builder will allow you to select one or more from a list of Entry Points. A person will have only one Entry Point associated with their record. This is set when the record is created.
The Entry Points will vary from church to church.
You want to find out how many people came to your church for the first time because of an enrollment in a team or sport. Select Equal Activities Ministry.
Then you can add another Condition Recent Attend Type, selecting New Guest and Recent Guest, and then select the program Life Group to find anyone with an Entry Point of Activities Ministry, who has also attended a Life Group recently.