Abilities which share cooldown

Is there a ability which can share cooldown?

Imagine Unit A cast spell X and it has a cooldown of 6 seconds, after spell X is cast, spell Y comes in and it takes the cooldown of spell X instead of having no cooldown.

If you still don't understand, for example, you cast stun bolt at a enemy that has a cooldown of 8 seconds. After you cast stun bolt, your ability stun bolt turns into another skill and retains the cooldown meaning that 8 seconds must past first and the icon must be there showing the cooldown

Is there any abilities which can do it or how do you trigger the cooldowns without removing the ability and then waiting?

Each spell has a cooldown group, simply put them in the same cooldown group.

It didn't work work as there is no cooldown group.

Kind of like the effects of having the shared cooldown abilities in the same spellbook?

No, the spell is supposed to occupy only one slot in the hero skills so it doesn't take up much space, explained above that how the abilities vary.

Dummy cast Channel with an altered spell base ID? It'd take ages to do if you had each spell giving different cool downs, though.

Maybe put them in a spellbook and use shared cooldowns?

Um... The last time I checked, this only happens with items. Items are the only type of object that can hold a cooldown group.

So, you want one ability to turn into another ability, but also keep the cooldown of the spell that was used last? Not only that, you want it to show that the ability was used? If it were that easy, I would have done it a LONG time ago. Believe me. To have it exactly like that, I think is impossible to do considering that there's no way to bend Warcraft III's mechanics on how abilities are dealt with. You can't even turn Channel into an auto-cast spell. I find that one disappointing.

But... I can think of one way to do it. It's nothing like what you want, but it achieves a similar effect. However, the only problem is, because it uses auto-casting abilities (which are the only abilities that detect a left and right click) you won't be able to target points or have an instant effect spell... Unless you know of a auto-cast ability that does that?

As for the question, I think the only way you're going to achieve the effect you want is to group the specific abilities within a spellbook. There is no such thing as an ability with a cooldown group, only items themselves have cooldown groups.

there is a way, by replacing the real 1st spell, with a exact copy of itself, but the icon and description of the real 2nd spell, on "unti begins casting an ability" event and (re)ordering the unit to cast the spell. Then replace that fake spell with the real 2nd spell, when the cooldown finishes.
however there are some problems you have to deal with. Even though, you already removed the 1st spell, it will still cast. so you would have to workaround, to prevent a doubleeffect, by adding a level to the fake-spell with the targets set to none and the manacost to 0 and set to the real level after casting, to display the right manacost. you also may want to use a own leveling system for this spell when using it as a hero skill, based on a dummyspell without icon to prevent level bugs, when skilling while having the fake-version

i attached my testmap. works quite fine, but i still don´t like that solution =/