Massive suppression of message in PM

Hi,

It'll be great if you could suppr a large amount of PM in a single shot.
One by one is a real pain, especially when you must suppr 10k of them :(

Or, and "archive" function would be great, so if needed it's possible to ask support for an archive file (with the PM ID) and the full conversation is still avaiable for legal purpose.

Thank you in advance if you could think about this solution.
Have a great day