sieve: store string list in varable

[whats_up]

Hi,
 
I'm working on a Sieve script and want to store a list of addresses in a 
variable to easily access the list multiple times later.
 
For example I want to transform this:
 

if address :is "from" ["daffy.d...@example.com", "porky....@example.com", 
"speedy.gonza...@example.com"] {
    fileinto "friends";
}

 
into something like this:
 

require ["fileinto", "variables"];

set "friends"  ["daffy.d...@example.com", "porky....@example.com", 
"speedy.gonza...@example.com"]

if address :is "from" $friends {
    fileinto "friends";
}

 
Any ideas on this?
 
regards Knut