Can folder-hook refer to a sub-directory mailbox?

[Chris Green]

It's a bit difficult to explain this.

Is it possible for a folder-hook RE to apply to all mailboxes in a
sub-directory?

E.g. can one produce an RE for all the sub-directories of ~/mail/folder?
All my actual mailboxes are two levels further down:-

    ./folder/france
    ./folder/france/jobs
    ./folder/france/healthcare
    ./folder/france/healthcare/tmp
    ./folder/france/healthcare/new
    ./folder/france/healthcare/cur
    ./folder/france/healthcare/cur/1601033995.000001.mbox:2,
    ./folder/france/healthcare/cur/1601033995.000004.mbox:2,
    ./folder/france/healthcare/cur/1601033995.000002.mbox:2,
    ./folder/france/healthcare/cur/1601033995.000007.mbox:2,
    ./folder/france/healthcare/cur/1601033995.000003.mbox:2,
    ./folder/france/healthcare/cur/1601033995.000005.mbox:2,
    ./folder/france/healthcare/cur/1601033995.000000.mbox:2,
    ./folder/france/healthcare/cur/1601033995.000006.mbox:2,
    ./folder/france/houseSitting
    ./folder/france/houseSitting/tmp
    ./folder/france/houseSitting/new
    ./folder/france/houseSitting/cur
    ./folder/france/houseSitting/cur/1601033995.000000.mbox:2,RS

The mailboxes are jobs (though it's empty), healthcare and housesitting.
Obviously I actually have lots more mailboxes in lots more
sub-directories below ./folder.  Can a folder-hook RE select them all?

I.e. does 'folder/.*/.*' work?

-- 
Chris Green