If a brand new student already has siblings enrolled in the school, you can link the new enrollment's application to the existing family ID associated with their siblings:
Click the EnrollMe tab on the left side of the page.
Select the student application (a selected application will be highlighted in yellow).
Select the correct family group from the Import to Family ID drop-down menu. The change will take place automatically.
Note: This can only be done if the application is for a brand new student.