It would be great to have a conditional state that if the hand and the ball are magnetically connected that the hand cycles to a specific hand state. Then when they are not connected, the hand reverts back to the base state.
Not sure I'm following exactly what you want to achieve. But I got this by having a cycle for the arms, with only one arm tagged with magnet, and a swap set for the ball, with one ball tagged, and then using the same trigger for both. Still needs some tweaking.
I am really just wishful thinking. I guess I am thinking more like Adobe Animate where you have the ability to set conditions that trigger other conditions. I was thinking for example, if the wizard picks up the crystal ball the hand changes from flat to holding pose until the wizard no longer holds the crystal ball.
You mean something like this?
Here are rigging and triggers I used