Metadata writing of hierarchical tags

Hi !

I'd like to know if it's possible to set the way that hierarchical tags 
are written in xmp.dc.subject tag for example.

If all level above a hierarchical child tag are checked, Digikam writes 
them like this, for example for the keyword oak :

plant

plant/tree

plant/tree/oak

This creates 3 keywords in this example, each representing a level.

Is it possible to set Digikam to write a child tag and its parents like 
this (flat list) :

plant/tree/oak

or

plant, tree,oak

The same question applies to reverse geocoding which creates as many 
levels as there are in the adress fields retrieved.

Thanks for helping.

Regards.

Pierre