asterisk users - Dec 2004 - Supporting "End User Line Features"

Sigh..

This shouldn't be so hard. Ok guys, I'm trying to figure out how to 
support end user features for my users. Perhaps some of them are typical 
verticle service features like *69, *72, *66, etc, you get the picture.

Here's my deal. Sure implementing them one by one is easy enough. But 
building the logic on the incoming side (PSTN calling my SIP customer 
for example) is a real pain:
1. Call comes in from pstn
2. is destination allowed to call forward?
3. If call forwarding is allowed, is it enabled?
4. If it's enabled, what's the number?
5. Is do not disturbed allowed/enabled?
6. Is call return allowed/enabled?
7. if call return is enabled, store the incoming callerid
8. etc. etc. etc

So a standard extension could end up being really really really long to 
support all these features.. Just seems so.. wrong considering that some 
of my customers might have no features at all. I seem to remember that 
Zoa mentioned that "goto"s were horribly slow and I'm planning on
really
loading these machines up with simultainious (100% G711 SIP) calls.

So does anyone have any ideas on some simple logic that doesn't require 
each and every call to go through all these steps? I can't seem to think 
of a way.. Other than doing funky pattern matches...

Then again, if the gotos arn't such a big deal, or if having 40-80 
actual steps before a call is sent to the phone is ok, hey, I'm ok with 
that. Anyone have any experience with that? It just.. feels so wrong.. 
Seems like a gosub might be what I need <shrug>

Any thoughts?

Heh, I know chances are that the solution is probably a lot more obvious 
than I'm making it. So if it is, please be gentle with me. :)
Thanks,
-Brett