Hello Patrick, My name is Indhurani, I’ll be happy to help you today.
Unfortunately, it is not possible to split a Teams group once it has been created. Any existing content that has been uploaded to the group will remain in the original group and will not be moved to the new groups. However, you can copy any content that you would like to use in the new groups.
If you want to use the same data, channels, and settings from an existing team to create a new team, you can make a copy and then choose how your new team is organized and set up. For more information: https://support.microsoft.com/en-us/office/crea...
Create a team from an existing group: https://support.microsoft.com/en-us/office/crea...
Hope it helps you. Please let me know if you still need further assistance.
Regards,
Indhurani