Wholly-owned sub (which holds the capacity rights) buys space on aircraft owned by partially-owned sub.
Looks to me not far off how the SIN-AKL flights are run - 3K (Jetstar Asia) number on a JQ-operated, VH- airframe.
So you'll have JQ-nnn being flown on a 9V- / 9M- airframe SYD-Asia-FRA.