Filtering categories & losing the will to live!

Hi,

Sorry about the link bait title!

I've started a new thread for this to ensure my explanation makes sense,and doesn't get lost down the page.

In Runway I have two category sets (sectors and regions).

I also have a collection called "jobs" with various properties (fields)

Job can only have one type e.g "perm, contract" etc Job can be in multiple sectors (category) Job can be in multiple regions (category)

I am passing a JS object via an ajax call to PHP to filter the jobs list accordingly.

My problem is this, how do I manage the and / or type relationship?

So my query would be something like

 $jobs = perch_collection('Jobs', array(                
    'template' => '_job-list-item.html' ,
    'filter'=>'jobType',
    'match'=>'in',
    'value'=>'perm','contract' // selected job types list
    'category' => $filters['categories'], // my array of categories passed back
    'category-match' => 'any',
    ));

but I need to match against two different sets e.g

    category = "sectors/pharmaceutical"
    or 
    category = "sectors/occupatinal-health"
    and
    category = ("regions/europe/france","regions/europe/uk")

Firstly am I approaching this correctly, i.e is my logic correct here? Secondly how would I approach this?

If anyone can help it would be much appreciated!

Many thanks

Lee