[TYPO3-Solr] SOLR RELATION sys_categories display by parent category

[Matt Clough]

Hi All,
Could somebody point me in the right direction when it comes to managing and displaying sys_category relations?
I am attempting to use SOLR as a staff directory. I have the indexer setup to index the staff records and index additional fields such as location, phone number etc. 

The problem I am having is with system categories.  

I have the following in the index configuration:

			category_stringM = SOLR_RELATION
			category_stringM {
				localField = categories
				multiValue = 1
			}

This works fine and correctly indexes all the categories. 

Some of these categories are have a parent category called department and others called projects.

What I would like to do is, on the results page, display the categories for department and projects in separate places.

Is it possible to separate out the categories based on parent category? Can this be done with fieldRenderingInstruction? Or do I need to index them separately? If so how would I do this?

Thanks

Matt