Need help with macro for mounts - situational and modifiers

[Einarr-the-shatar (Einarr)]

I currently have a macro that will summon a flying or non flying mount in the appropriate type of zone. However, I’d like to also have the option to use a modifier to be able to summon a specific mount, e.g. Grand Expedition Yak. Is this possible?

Current macro code is:

#showtooltip
/cast [flyable] Teldrassil Hippogryph; Kaldorei Nightsaber
/dismount [mounted]

Thanks.

[Fleckfell-blackrock]

/cast [mod:alt] Grand Expedition Yak; [flyable] Teldrassil Hippogryph; Kaldorei Nightsaber

you can change mod:alt with mod:shift, mod:ctrl and by holding that key with a leftclick will get the Yak

or you use /cast [btn:2] Grand Expedition Yak; [flyable] Teldrassil Hippogryph; Kaldorei Nightsaber;

Leftclick works as usual, rightclick will get you on the yak

[Kelithria-the-shatar]

This one summons an appropriate mount depending on the environment, but also gives you the option of summoning a repair mount if you hold alt, your ground mount if you mouse over a unit, or your flying mount if you set a focus target first, (because you occasionally might prefer to ride your horse in flyable zones or want to fly out of some water).

#showtooltip
/stopcasting
/use [mod:alt]Repair Mount;[@mouseover,exists,nodead]Ground Mount;[@focus,exists,flyable][flyable,noswimming]Flying Mount;[swimming]Underwater Mount;Ground Mount