Permissions configuration

Question

We are trying to set up an xserve with the following permissions,
On a share, where all users have read/write access, we would like the owner of each document to have full permissions, and all other users to have read only permissions, and not be allowed to trash documents.
We have the group, lets say Group1, setup to Read Only, and can get the permissions to look right, i.e.
User1 makes a new document, and has read/write permission, with the Group1 permissions at read only, but when User2 logs on, who is a member of Group1, he can throw the document in the trash...no questions asked, but can not change the document.
I not understand, we are using ACL and POSIX permissions on this share. Is there a permission or user, that will give us this setup??

Answer 1

I know this may seem simple, but I still feel it does not work.
We have made a share, Test, user unknown, group test. User has read/write, group has read only.
Two users, test1 and test 2.
A file is copied to the server as test1, I then login as test2, and look at the permission, that are correct, test2 has read only permissions, and test1 is the owner with read/write. The problem is that test2 can throw the file out, witch in my understanding, is more than read only!!!!! I hav screen dumps of the permissions....if you do not believe me. There must be a way of setting the permissions up, so only the owneer has fuld rihgts to a file/folder. Any ideas welcome. We have tried to make a deny rule for the group test, but then nobody can throw the files/folders out.