some new per usergroup based permissions?!

[Muellmann]

I would like to have added extra usergroup permissions for a more exactly definition how usergroup is allowed to edit what.
Everyone knows, that pro usergroup can be checked a permission "can edit own posts".
This includes unfortunately own threads and own posts without making there a difference.

So the first what I would need, is to differe in a permission between posts and threads,
so there should be like a new per usergroup option:
"can edit own threads" additional to "can edit own posts".
So if I check "can edit own posts" on a usergroup where someone belongs to, so this user
can only edit own posts, but not own threads.

"can edit others posts" and "can edit others threads" are two permissions which I also miss
per usergroup. Maybe I want not make someone moderator immediately, but I want that this person could edit other peoples posts for example only for correction purposes.

What I also miss is the option "can edit own attachments". Maybe I want my users only be able to edit them threads / posts, but not them once uploaded attachments.
So such "subpermission" would be very handy. If I don't check the "can edit own attachments" for a usergroup, the users in this group will be not able to remove for example them own uploads again, but they could be able to edit their text if the "can edit own threads" option would be specified.

The background is: At the forum which I am the advisor of, people use to empty their
threads and like to remove their attachments to give our administration pain and troubles.
Now we could go the hardliner way and disallow the option "can edit own posts" with the fatal consequences, that members are also not able to edit any simple replies which they
have once made. This would end up in a big storm of protest, so there's nothing what we can do about, except of endure the condition, that they mess up all them uploads freqently.
I know there's also a "edit expiry time" on posts which can be set in ACP, but it is not our
problems solution and we switched this option even off.

New permissions on a per usergroup base:

• can edit own threads
• can edit others posts
• can edit others threads
• can edit own attachments

Every tip on how to realize it is highly appreciated. My and the administrations knowledge
isn't enough to find out something helpful. We would donate for a solution, please help us.