Map Editor: unit selection for defense and transport

When selecting defense bonuses for units, and also when selecting what type of unit another will transport, it would be useful to have the ability to select the type of unit, such as "Ground: Main Defense". It's not a huge deal, but I have often wished such a selection was an option, rather than being limited to transporting one specific unit, or just being stuck with transporting everything that is transportable.

Either that, or just make the transport menu the same as the defense bonus menu, where you would be able to select more than one unit for transport.