Permissions for subfolders

Thank you for the great product!

The question concerns the distribution of rights to shared folders.
Initial conditions:
User Alice is in the Read_Group group;
The folder /test is shared for Read_Group only for reading; Issued write permissions for the folder /test/test3 to Alice user;
Alice has no write access to the folder /test/test3.
How is it possible in this situation to grant permission to write to the user Alice without removing her from the group Read_Group?

Nextcloud 13.0.5