ACL on share points doesn't seem to work

Hi Everyone,

I have a server set up, with a series of share points on it. One of those folders is "Marketing", and the Marketing team has a boss, who is the only guy who should be able to create folders within that share.

The people in the Marketing group, should have access to write and delete files, but not create folders.

Here's the setup:

Users/Groups:

• John (boss)
• Roger (one of the Marketing employees)
• John and Roger both belong to the Marketing group

Share point ACL:

• Marketing / Allow / Custom ( full read, write attributes, write extended attributes, create files, delete ) but not create folder, delete subfolders and files
• John / Allow / Full Access

As last detail, all users are on Apple computers.

Problem

John is able to do everything he should, create files, folders, etc.

Roger on the other hand, can only read.

Question

Does the ability to write files, require the ability to write folders? If I let Marketing group write folders, Roger's access works. If so, is there a workaround?

Thanks!