Here's a problem Zcoretri and I were contemplating the other night. Again, we were playing with Invaders by using /spawn combine and getting our spawns cleaned up - when it occurred to me that "placeholder" spawns will likely need a different spawnscript than their rare/named pop.
Scenario:
We combined a bunch of sapswill grunts and invaders into the same spawn group. Now, occasionally an invader will pop, and mostly, a grunt. Well, the Grunts are not supposed to move... only invaders. But, in our setup, the grunt starts moving towards the guards.
Without putting NPC-checking logic into the spawnscript, I cannot think of a way to ensure they still behave like placeholders, yet act differently when they spawn.
Suggestions?

A better example of this is a sequence of placeholder mobs that pop until a Boss or rare pops.
Problem:
spawngroup_id 1 contains 4 spawns @ 25% change to pop each time. When you pop any of the placeholders, they have a spawn_script that has them act a certain way, sayings, emotes, shouts, whatever.
That 25% chance the Named/Rare/Boss pops, you might have that mob do something completely different. Give out a quest, attack everything in the zone, say different sayings, emotes, shouts, whatever... because, he's a completely different spawn. By forcing the spawn_script to cover every entry in the spawngroup, we are limited to how we can cause different interactions based on different spawns.
Solution 1:
Move the spawn_scripts field from zonespawngroup to zonespawnentry -or- zonespawns to allow attaching a single spawn entry to a script for optimal configuration. This will end up in more data to enter (the above example would have 1 unique script on the boss, but 3 entries identically the same on the other 3 spawns in the group) but offers the most configurability.
Solution 2:
Leave spawn_script in zonespawngroup, but ADD another spawn_script under zonespawnentry -or- zonespawns, and teach the server that if the zonespawnentry.spawn_script is blank, fall back to use the "general" one in the zonespawngroup.spawn_script field. If it is not blank for that particular zonespawnentry.spawn_script, load that script instead.
The effect would be that 3 placeholders spawn at 0,0,0 and shout "I'm gonna keel j00!" while the 4th, rare named spawns and shouts "I have an important mission for j00!".
Make sense?

Check out my post here: http://eq2emulator.net/forums/viewtopic.php?t=896
Let me know if that solves all your problems.