Last night we had BG Xs fighting A, B and Cs. C is counting as an overlap.
AAAABBCCC
XXXXXX
The B group routs but the X group can't pursue as it's still fighting the A group.
When it's the C units turn IIRC it can slide along to line up with the rightmost X - this isn't a charge.
It could also advance down and move past the X group.
Is the C group allowed to wheel just short of the flank of X and then in its next turn charge into the flank of X?
Actually, thinking it through I'm sure it can. But I'll post anyway...







