How do Errata relate to Updates?

[Don Hoover <dxh yahoo com>]

Ok, I am trying to build my kickstart environment, and
am a little confused about Errata.

I have been watching the errata and getting emails
etc. for sometime now and I have noticed that they do
not reference a particular release such as RHEL4U2,
they only say RHEL4, RHEL3 etc.

So I am tring to figure out, how should I plan on
using errata to keep current?

Do errata get rolled into the next update version? 
For instance, will current errata get rolled into
RHEL4U5?  I picked a few erratas, and followed their
trail via the notices and bugzillas's but they never
mention if they get rolled into an update or not.

Should I have all my systems apply all the errata from
a seperate yum directory or should I put the errata
into my distro distro directories (eg put it into
RHEL4U2, and RHEL4U3 kickstart directories) and then
redo the comps.xml for those kickstart directories?

Anyone have any insight?

---
Don Hoover
dxh yahoo com