Sieve filter rule - postfix-mta

Question

I want using SIEVE to filter e-mails in a postfix/dovecot installation.
Assuming there are multiple recipients in the TO field of an email.
Is there a SIEVE rule to match an email if the TO field contains an email address with a specific domain name and at the same time contains an email address with a domain name different to that specific domain name?
For example, let the specific domain be "example.com".
TO: a#example.com, b#abc.com -> MATCH
TO: a#xyz.com, b#abc.com -> NO MATCH (since no address with example.com)
TO: a#example.com -> NO MATCH (since no address different to example.com)
TO: a#example.com, b#example.com -> NO MATCH (since no address different to example.com)
TO: a#abc.com -> NO MATCH

Answer 1

What turned out to working for me is the following:
require "regex";
if allof ( address :domain :is "To" "example.com",
header :regex "to" "#[^(example.com)]+"
) { ... } else { ... }
Thus, you can match "some domain different to example.com" with the statement header :regex "to" "#[^(example.com)]+"
SIDENOTE
Some thoughts about Kaspar's suggestion (which did not work for me).
It turned out that
if address :domain :is "To" "example.com" {
matches if any of the emails in the To-field contains example.com. The not-statement just negates this result. I.e.
if not address :domain :is "To" "example.com" {
matches if none of the emails in the To-field contains example.com.
As a consequence, combining both statements within allof does never match.

Answer 2

[Edit: The following rule does not work, see the other answer for the reason.]
I'm not an expert on the Sieve mail filtering language, but have you tried something like the following, using address, not, and allof?
if allof (address :domain :is "To" "example.com", not address :domain :is "To" "example.com") {
…
}

Answer 3

You can use relational extension to ensure the existence of an email address with a domain name different to the specific one. See Extended Example section of RFC5231.
require "relational";
if allof (
address :domain :is "To" "example.com",
address :value "ne" :domain "To" "example.com"
) {
# match
} else {
# no match
}