I understand...
But I would do differently...
In next version 3.2, the filters will be unified between ALL layouts of the same page. I encounter a compatibility problem with that.
In fact in the new way (native Joomla), the filters are declared such as XML forms.
But it is impossible to declare multiple sets of filters. So the declaration of filters are shared between pages.
It is not a problem for us because then it will be possible to instance individually the filters. I found a workaround for keeping this cook ability.
In definitive, filters will be declared at the level of the table (not the layout)
Then the builder will allow you to choose wich filter to instance in the layout.
So... to return to your problem...
It will be covered in the version 3.2 because you will NOT need any layout for instancing a filter in the model.
The version 3.2 is quite a revolution but a lot of work.
The objective of 3.2 is to fit better to the Joomla native framework
Know more :
j-cook.pro/index.php/news/16-news/233-less-is-more
Hope it will fit your needs