Hail Caesar Flank attack question.

[racm32]

Red Players turn. A charges Blue B. A and B fight to a draw and both stand. Blue players turn. C charges into A's flank. For the first round of combat will C get Clash dice and B get sustained or is one considered in support? Will A be at sustained or clash, fight both individually, or spilt (mandatory/optional?) their dice against C & B. If A survives and stands, on Reds combat phase are they still considered flanked or turned to face both C & B?