Using the options below will only be necessary if your league is awarding negative ranking points to a team that losses by forfeit or if you are using win percentage/points calculation as a ranking criteria.
To have your schedule accurately reflect a double forfeit you will need to create a fake team. Then you will schedule this new team against each of the two teams that forfeited and have them forfeit to the newly created team. Please keep in mind that the team name you create will be visible on the public schedule area.
After you have created the two games you can go back and cancel the team you created. This will remove the team from the standings area and leave the other two teams with the loss by forfeit on their record.
If you are using win percentage/points calculation as a ranking criteria you will need to create two games and score them according to your standings rules. These games will stay on the schedule after the created team has been cancelled but the team will be removed from the standings list.