On new and migrated Firmex projects, you can set folder permission by group. To do so:
In Firmex, click Documents.
On the left side of the Documents page, right-click the folder whose permissions you want to change, and select Set Permissions.
Find the group whose permissions you want to change. Change the group's Content Role from the Content Role pull-down next to the group's name. For example, to hide the folder from a group, select the No Access content role.
Click Apply to Folder to apply the change to the selected folder, or Apply to Folder & Subfolders for the change to apply to the selected folder and all of its subfolders. Note: Please refer to the 'Permission Icons' section in this permission guide for help identifying permission icons.