Squirrel and acts_as_rails

I have been using Squirrel (http://thoughtbot.com/projects/squirrel)
for performing rails searches. It really takes the thinking out of sql
conditions and makes it so much more like normal ruby syntax.

I have recently been using the acts_as_tree gem(http://github.com/
jcnetdev/acts_as_tree/tree/master) for a Group model that has
children, grandchildren etc. Squirrel works well for the children and
parent methods since these are normal associations but for methods
like “ancestors” and “all_children” which are recursive methods ,
squirrel won’t work.

I don’t fully understand how squirrel uses associations. Can you think
of a way that squirrel could be used in this kind of way

Group.find(:all) do
ancestors.name.contains?(“Department”)
end

Many thanks

Anthony