How to use join on nested association?

[Grestorn]

I have a complex structure which I'll simplify for this example:

class Site {
...
}

class Series {
  Site primarySite
  Set<Site> additionalSites
  ...
}

class Story {
  Series series
  ...
}

I need to select all stories associated with a Site and make further more detailed selections with that.

First I select all series and that works fine using this:

    def siteSeriesCriteria() {
          return Series.where {
              join("additionalSites", JoinType.LEFT)
              or {
                  eq('primarySite', thisSite)
                  additionalSites {
                      eq('id', thisSite.id)
                  }
              }
          }
   }

   list = siteSeriesCriteria().id().list()

That produces the intended SQL:

select
	this_.id as y0_
from
	series this_
left outer join series_site additional3_ on
	this_.id = additional3_.series_additional_sites_id
left outer join site additional1_ on
	additional3_.site_id = additional1_.id
where
	(this_.primary_site_id =?
		or (additional1_.id =?))

But when I try to use the deeper nested level that doesn't work anymore:

    def siteStoryCriteria() {
            return Story.where {
                series in siteSeriesCriteria().id()
            }
    }
   list = siteStoryCriteria().id().list()

Now the join is no longer a left outer:

select
	this_.id as y0_
from
	story this_
where
	this_.series_id in (
	select
		this_.id as y0_
	from
		series this_
	inner join series_site additional3_ on
		this_.id = additional3_.series_additional_sites_id
	inner join site additional1_ on
		additional3_.site_id = additional1_.id
	where
		(this_.primary_site_id =?
			or (additional1_.id =?)))

I've read that join() only works on the tree root of the Criteria-tree. But how am I supposed to solve this?

I've tried to add
join("series.additionalSites", JoinType.LEFT)
to the nested criteria, but that doesn't work either. I'm stumped here...