A bit of theorising but..
Engine 1/outer wing leak - centre closed because you can't use APU bleed and onside closed to avoid cross contamination to the pack or feeding the wing leak.
Eng 3/inner wing leak - right closed to avoid the cross contamination and centre open to allow use of APU bleed if required.
Looks like the L/R opening allows for Pack Bay Vent and Hyd Rsvr Press as well.
"When an engine or a wing bleed duct is affected, the applicable bleed source is closed, and the crossbleed valves are closed, as appropriate."
Happy to be corrected, always learning
