The below instructions will demonstrate how to properly setup divisions with combined age groups.
All teams must be set to the higher age in a combined division. For example, in a division with U14 and U15 teams, the teams must all be set to U15. The reason being, the division will not be ranked if it appears the division is set as U15's playing down to U14.
Create the division with the higher age being the age for the division.
Change the event age group for the teams playing up. Click "Teams", select the team(s) you need change, then change the "Event Age Group".
You can now populate the division.
Click here for instructions on populating and seeding divisions.