We decided not to create a new team for these 6 weeks (as this new team would have spent at least 3 weeks to adapt to each other) but to keep a team a team.
In order to manage this constellation we set up a board that works like a feature board but which visualizes the work of the 2 teams:
The cards on the actual board are not empty, this picture is photoshopped.
We drew 3 rows, each row representing 2 weeks time. The first column was for Team A, the second column for Team B and in the third column was the done column.
In order to visualize which stories are in progress we used pins in the shape of a flag:
Each team has its own color (Team A has white flags, Team B yellow flags). If a task is in progress, it's "flagged". In order to keep track of who did what, the index card stays flagged once it's moved to the "Done" column (you can see the little flags in the Done column on the first photo).
After 5 of 6 weeks I can say I'm really glad we used this board to organize the work of the 2 teams as it made organizing really easy and transparent.