You only need to edit one of them. Editing any of the others will break it.
Really? The sortindex numbers on all 6~7 BINXes included in a single hair recolor are identical, at least in custom hairs. If I want to group them together for all age groups, not for just one age group, shouldn't I give a new sortindex number to
all BINXes included in a given recolor? I've done it on several hairs without breaking them.
I did notice (when I was checking things in game) that the Frag. sort index number changed; higher numbers were at the front of the catolog with CC - lower CC numbers in the middle, and when the Eaxis hairs started the numbers got larger again (kindof a B.C./A.D. thing.)
Changing sortindex number (hex) will change Frag sort index number (dec) which you can see in CAS debug mode, yes. For example, if sortindex number on one of blond recolor is 0x000010EC, you give 0x000010ED to another blond, 0x000010EE to yet another blond... you get the idea. The recolor with the largest sortindex number will show up first in CAS or Bodyshop, but only within a same bin. EAxian skins are sorted into EP bins, which the game uses to sort skins in accordance with the EP order.