Configuration question about a domain list for a http.req.host comparaison

[Damien Desmarets]

Hello,
I have 1 question for you. I haven't found the response in the
documentation/wiki. I think you have a big job to wrtie a good
documentation ... the current is really poor !

So the question.
I have a list of differents domains:
azeazeaze.com
eruigeiogr.com
zezeirjiorf.com
...

My configuration file is actually like this:
if (req.http.host ~
"^(azeazeaze.com|eruigeiogr.com|zezeirjiorf.com|...)$") {
    set req.backend = principal_delivery;
} elsif (req.http.host ~
"^(aazeazeazeaze.com|azeiazjeaioze.com|azejoazjeaiozejoaz.com|...)$") {
    set req.backend = pictures_delivery;
} else {
    error 403 "Not supported"
}

The regex comparison is very big with maybe 100 domains. It's not clear
inside my file, and difficult to made change.
Is it possible to include those domains in a list and match this list to
the req.http.host. Like this maybe:

#define DOMAINS_PRINCIPAL_LIST "domains_principal_list.txt"
#define DOMAINS_PICTURES_LIST "domains_pictures_list.txt"

if (req.http.host ~ DOMAINS_PINCIPAL_LIST) {
    set req.backend = principal_delivery;
} elsif (req.http.host ~ DOMAINS_PICTURES_LIST) {
    set req.backend = pictures_delivery;
} else {
    error 403 "Not supported"
}

I know the constant don't contain regex valid content but it's a
pseudo-code to show you the idea.

And my file "domains_principal_list.txt" contains for exemple:
azeazeaze.com
eruigeiogr.com
zezeirjiorf.com

Is it possible to do this in VCL origin configuration?

Thank for your help.

Regards,
Damien Desmarets