I think you will have to add some local time signatures at the desired locations. Open the popover (shift+m), write 4/4 and press ALT+enter when closing. These won’t show in the other players, but they will show in the score.
Amanda, what you’re asking for is a bit non-standard, since you wouldn’t normally add a “cautionary” time signature at the start of the system for any other kind of player. What would possibly help them would be to make the time signatures a bit larger, which you can do by selecting the time signatures and increasing their size via the ‘Custom scale’ property in the Common group.