This is one of those things that every time I load a pose I wish I had but eventually slips out of my mind after a while so I never fully realize how much I really needed it. Amazing QoL stuff!
If there's anything else I would love to see here is the ability to set an alignment point to multi person poses; this should be useful when loading poses for characters with different heights than the original, like setting the pelvis or hip bone as an alignment point and loading the pose on a taller character so the hip/pelvis are aligned and won't screw up the focal part of the pose... etc. hope that made sense :)
For now, I'm leaving the plugin as it is.
Your request would probably be very difficult, if not impossible, to implement reliably.
Manual adjustments for people with different sizes will most likely be unavoidable.