[nmh-workers] how might I make sequence 'bar' where 'bar' is all but msgs in seq 'foo'?

[nmh]

Given a sequence 'foo', how can I get the complement, i.e. all messages in the
folder, not in sequence 'foo'?  I want to save the results to sequence 'bar'.

I could write a shell script, but can this be done more directly?

Thanks for all your work!  I would seldom use this, but it would be nice to 
know.

--
thanks,
Tom