make dormant marks permanent (no gnus-summary-limit-to-registry)

Hi


Is there any way to make dormant marks permanent?
I add dormant marks to the messages of my imap group

But after closing gnus and restarting emacs they are gone.

Rationale

I want to use gnus-summary-limit-to-marks
to display certain message.


Another option would be to use the registry, but
gnus-summary-limit-to-registry does not exist and seems difficult to
implement, at least I was unable to do it.


Regards

Uwe Brauer