Unfortunately that still won't solve the issue -- flying mounts are technically able to be summoned on the ground, so they will still be summoned in Draenor using the "summon random mount" feature.
As a workaround, you can install my addon
AnyFavoriteMount which replaces the default "summon random" logic to avoid summoning flying mounts when you can't actually fly, even if the area is labelled as flyable. (Its primary feature is to let you set class-specific mounts (eg. warlock dreadsteed) as favorites, since for some reason Blizzard does not allow that normally, but you can still use the addon and just ignore that feature.) Then you can set your two mounts as favorites and use the "summon random" feature as p3lim suggested, and get the right mounts in the right areas.