Overlapping Groups with different rights / how to prioritise?


We have setup our Nextcloud for a small team that is divided into 2 Groups on Nextcloud.
There are also 2 folders for these 2 Groups.

Group A has all the rights to Folder A, which they also sync
Group B should have read only rights to Folder A which they shoud not sync

I have 2 people in both Groups and Nextcloud does not give them all the rights even though they are in Group A but seems to prioritise their Group B read only settings.

How can i fix this? I want the “higher” rights to be prioritised.

Thank you very mich for any tips.