Hi @dave1167
This is not currently possible 'out of the box' and I'm not sure if some of the advancements in the filters of the forthcoming Cook 2.5 will help...
In the meantime, to workaround this, I'd recommend taking a copy of the ajax combo class & assets, rename it (them) and then call this instead of the regular class in your filter. There might be an easier way, possibly by adjusting the displayAjax() method in your view but, I guess it depends how many layouts in which you wish to call this filter.
Hope it helps!
Gez