Abilities Sharing Cooldown

If possible, how can I create several different unit abilities that share a cooldown? (So that a single unit can choose to cast one of them - and then they all cool down.)

EDIT: Oops. This is extremely misleading. The cooldowns will be on the same unit, "several different unit abilities" meant several abilities that a single unit would have, and "they all cool down" meant all of those abilities on that one unit, not on all of them.

You could give each spell a requirement of a unit. When there is no cool-down, the player has control of this unit (so the spells can be used). When the player uses a spell, remove this unit for the length of the cool-down. When the time has passed, give the unit back and the spells should become usable again.

Yes what Ammmorth said is the way it can be done but beware of the side effects.

If you do it this way you can only have one unit per player holding the ability... You also don't get the nice little clock effect, but if the cooldown is short enough it won't matter.

or if your spells don't need triggers you can use a spellbook ability

well... it could be done actually, even with a nice clock effect, ok...

- you have this group of unit with this ability
- one of it casted the ability.
- you detected it, now do this
- pick all the other units in the group and add a dummy ability (channel?) that share the same ability cooldown with your original ability. Also, remove the original ability if you don't wish to cause any trouble
- add the dummy ability to all the picked unit and order them to cast it on the ground immediately.
- now spells goes to cooldown, so remove the dummy ability and readd the original ability

tada, all the units share the cooldown!

Oops. I just realized my question was extremely misleading. Thanks for the clever answers, but my question is something else:

There is a single unit, with multiple abilities. I want the unit to have to choose one ability, then the abilities sharing the cooldown all start cooldown. Obviously, however, each of these abilities has a different effect.

The application is a little bit more complicated, but this problem is currently the stumbling block. I figured there was some easy way of doing this, like creating all the abilities from the same base ability or something like that, but I didn't know how.

So, what you're suggesting is that I make the abilities all have the same order string? Won't that just make it so that when I tell the unit to cast any of them it'll instead default to casting some other ability? Should I use a channel derivative for each of them? Do they have to have the same targeting parameters?

Just to make sure I'm clear about what I'm asking for, let me set up an example scenario:

I have a unit, we'll call him Archmage. Archmage has three abilities: Summon Water Elemental, Blink, and Storm Bolt. Archmage can choose to cast one of them. Archmage casts Summon Water Elemental. A water elemental is summoned, and then all three of Archmage's abilities begin cooling down. The same would be true if the Archmage casted either of the others (except obviously he would have blinked/storm bolted instead of summoned a water elemental.)

That is what I want to be able to do. If it's not possible to do with each of the abilities having different targeting parameters, then that's okay too, just less convenient.

And by the way, thanks for your help.

Hmph I do remember one of the hero arena had something like this, anyway, you should try changing the things to the same order id, and see what happen, if it don't work, i'll suggest another method for you :)

Spell books are the easiest way.

Could you please elaborate? What do I do?

Spellbook has an option of forcing all abilities within it to share a cool down time. The downside would be having to click the spellbook and then click the spell you want to cast instead of just clicking the item.

You can find a good deal of information on using spellbooks if you do a search.

Oh sweet, thanks! The spells I was trying to have share a cooldown were within a spellbook. I missed that variable.