In any single-well process one of those is the substrate and
this is a poor-quality common connection. Drive one body,
drive them all. Probably not the plan.
More complex FEOL flows can give you N and P wells both
reverse-biased-junction isolated. These, you may drive
independently. Bearing in mind that your body driven
MOSFET can easily show its ugly base driven parasitic
BJT (injecting well or substrate currents to cause some
trouble nearby but unanticipated).
Just because you have access doesn't mean that
touching it will make good things happen.