You could also use castsequences as the groups of attacks instead of just lists of spells.

I use the cooldown on other spells to keep things from spamming. For Flame Shock on my shammies, I know I don't want to recast it every time it's available, only when the DoT is going to fall off, so I build it as a sequence of shocks

Enhance -
Code:
/castsequence [@party1target, exists][@target] reset=target/5 Flame Shock, Earth Shock, Earth Shock, Earth Shock, Earth Shock
In this on, Flame shock won't go off again until I either hit my reset conditionals or I've fired off 4 Earth Shocks, which should be about 30s {glyphed Flame shock for longer dot duration}. 3 Earth Shocks would do if she wasn't using glyphed Flame Shock.

Resto -
Code:
/castsequence [@party1target, exists] [@target] reset=target Flame Shock, Lava Burst, Lightning Bolt, Lava Burst, Lightning Bolt, Lava Burst
This one goes on the same principal, except she uses Lava Burst instead of Earth Shock to time it out. The Lightning Bolts are just there for a little extra damage and don't effect the timing aspect I'm after.

I also do the same for totems
Code:
/castsequence reset=5 Healing Stream Totem, Grounding Totem, Searing Totem, Healing Stream Totem, Grounding Totem
Searing totem has a 1m duration, but no cooldown. Healing Stream totem has a 30s cooldown. So the 1m combined it would take for dropping HST twice will keep me from repeatedly spending cooldowns to drop Searing over and over.