Originally Posted by pinniped

Unlikely IB is willing to short-check a simple itin like this with a "normal" connection. You'd have better luck if an overnight was involved or some other oddity.

Maybe go to Barcelona, spend a couple days there, and go back to Madrid via flight or train? Both are wonderful cities more than worthy of a visit.

Seems like moving a couple hotel bookings around shouldn't be too hard unless there's some crazy-huge event going on in either city.