Newbie question about DNS & Granitecanyon

[STZ]

I hate feeling like an idiot, but I have little knowledge of exactly how DNS
works.

What I'm trying to do is run 3 domain names through one ISP hosting company.

I'd like:

1. www.domain1.com to point to the root of my ISP.  This is provided free
from my provider.  No problem here.
2. www.domain2.com to point to www.domain1.com, so when someone types
www.domain2.com they get rerouted to www.domain1.com.  Is there any way for
them to continue to see www.domain2.com in the URL, even though they are
seeing the content from www.domain1.com?
3. I'd like www.domain3.com to be stored in a directory under
http://www.domain1.com. For example, I'd like www.domain3.com to be actually
in www.domain1.com/d3/

I've been looking at Granite Canyon, trying to figure out if it can do these
things, but again I am a newbie.  Task 2 above sounds like it might be
doable by GC, but I'm having a hard time understanding the lingo in the
config file GC wants me to edit.

The config file reads:

"; The IP addresses below are reserved for networks
; not connected to the InterNet. They are not routable by
; most publicly accessible backbones and are here as an
; example only.

; navy.zaske.com.  IN  A  192.168.0.3

; some useful puns that cannot be CNAMEs because
; they are referenced by MX records, below

; mail1.zaske.com. IN  A  192.168.0.1
; mail2.zaske.com. IN  A  192.168.0.2

; an address for the zone itself

zaske.com.       IN  A  205.178.180.3"

Is this last line the spot where I'd enter the IP address I'd like zaske.com
to point to?  Can anyone point me towards a company that might be better
than Granite Canyon?  I am willing to pay a fee, but my current provider
wants to charge me $2.50 a month for this service.  It seems like all I am
asking is to change this config file to point domain2.com to the same IP
address domain1.com points to.  Doesn't sound like it's worth $2.50 a month
to me.

Task 3 sounds even more complex, and I'm not sure how domain1.com/d3/ would
get an IP...it has me stumped.

Thanks for the help guys,

-=STZ=-