A no cast modifier?

Im new to MultiBoxing and am starting with two elemental shamen.
I have focus/follow macros etc set up and have a LB macro to attack my focus target...I have done the same thing for Earth Shock
Although this is where I am stuck I'd like to keep the macro's as they are but have a modifier in them so at time I dont want my secondary toon to cast LB or earth shock as to save mana for heals.
for example this is what i have at the moment on the secondary toon
/cast [target=focus-target] Lightning Bolt
how do I modify it to say for example if i press alt it still casts on my main but ignores on the alt
(im using keyclone)
thanks for reading as you can tell im pretty clueless with this.

You can add the ALT+Key to the KeyClone do not pass list which means it will cast on whichever one is in focus and not the other one.

Or you can modify the macro several ways (only on 1 character).
All modifiers:

Code:

---

/cast [target=focustarget, nomodifier] Lightning Bolt

---

Alt:

Code:

---

/cast [target=focustarget, nomodifier:alt] Lightning Bolt

---

or:

Code:

---

/stopmacro [modifier:alt]
/cast [target=focustarget] Lightning Bolt

---

Just what I needed
thanks :)