>>>>> In <87hcpwkiur.fsf@call.dachary.org> Loic Dachary wrote:

>        I wanted to see all mails from OR to a someone. With
> gnus-summary-limit-to-from-to one can see all mails coming from
> or sent to yves.guiard (for instance ;-)

Isn't it better to be `gnus-summary-limit-to-from-to-cc'?  In
addition, isn't there a use of excluding ones matching a regexp?
;-)

> +(defun gnus-summary-limit-to-from-to (fromto &optional ignored ig)
> +  "Limit the summary buffer to articles that have from or to header that match a regexp.
> +If NOT-MATCHING, excluding articles that have from or to header that match a regexp."

I tried improving it modifying `gnus-summary-limit-to-recipient'.