Tagging/Sorting Groups

I'm having problems trying to tag groups and wonder if anyone could help.

In the GH file attached I basically have a table, with three legs. The table is split up into layers, which include holes for dowels, which will be CNC'd. What I would like to achieve is to tag each part in a group, including dowel holes, with its relative layer number, 1 to 47, and the name (suffix) i.e. A, B or C. So, from top to bottom the main body would be A, where it splits to the next leg #-B and to the 3rd leg #-C.

My hope is to then nest each part along with its tag.

At the moment I have only been able to tag each contour slice of the table BREP. This does not include the holes. When I group the contours with the holes, I cant find a way to tag them all together. 

Also I'm struggling to find a way to sort items so that all tags in one leg have the same suffix. 

I'm still fairly new to Grasshopper, and trying to get my head around things. Any help or advice would be appreciated. 

Thanks, Adam.