Filter one-post thread only ?

[Xavier Maillard]

Hi,

In order to clean up and to trash out as many posts as possible in
several mailing lists I did not check lately, I am trying to find a way
to limit the current display to messages matching this requirements:

1. post older than 1 month
2. one-message thread only (a post and no followup/answer).

Do you think this can be done ? In case you do, then how ? :D

Thank you very much.

/Xavier