Given a bunch of circles I would like the UV packing to be sorted by a primitive attribute either respecting 1 or 2 dimensions.

So instead of the packing being somewhat random:

I would like the layout to be weighted/sorted by the attribute (colored red), like in this mockup:


Same for two dimensions:

mockup desired result:


Is there already a way that I may be missing to do something like this?
Scene attached (images from UV view)
Thanks
prb

I guess I'll have to do an RFE

Cheers