Save inherited object to separate collection in Mongoid

I read up to inheritance in mongoid and it seems that all inherited classes will save in the base class, e.g.

class BaseClass
end

class ChildClass1 < BaseClass
end

class ChildClass2 < BaseClass
end

It seems that all these store in the BaseClass collection.

I actually want them to store in separate collections, e.g. ChildClass1 - collection and ChildClass2 - collection.