grab with click and automatic ungrab is posible?

For usage reasons, I need the mouse to be grab only when clicked, and never when the pointer passes over the guest window.

so I have disabled "automatic mouse grab"

But it would be very helpful for me to ungrab the mouse when the cursor leaves the window, since sometimes I do not have a keyboard nearby to press ctrl + alt, only mouse.

Can you have both cases at the same time?

thanks