I guess what you are looking for is a robots.txt entry like this:

User-agent: *
Disallow: /www.example2.com

Let's suggestion you have more than 100 'parked' exampleNR.com URLs, but don't want to write a line for every single one of them...use this:

User-agent: *
Disallow: /www.example

The problem is, it actually is not officially supported, but many robots like Googlebot are able to understand those easy wildcards. RegEx are definitely not supported. for additonal information

UPDATE

Deleted the trailing asterisk since robots.txt uses simple prefix matching anyway. Thanks for your attention, w3dk

I guess what you are looking for is a robots.txt entry like this:

User-agent: *
Disallow: /www.example2.com

Let's suggestion you have more than 100 'parked' exampleNR.com URLs, but don't want to write a line for every single one of them...use this:

User-agent: *
Disallow: /www.example

The problem is, it actually is not officially supported, but many robots like Googlebot are able to understand those easy wildcards. RegEx are definitely not supported. for additonal information

UPDATE

Deleted the trailing asterisk since robots.txt uses simple prefix matching anyway. Thanks for your attention, w3dk

I guess what you are looking for is a robots.txt entry like this:

User-agent: *
Disallow: /www.example2.com

Let's suggestion you have more than 100 'parked' exampleNR.com URLs, but don't want to write a line for every single one of them...use this:

User-agent: *
Disallow: /www.example*

The problem is, it actually is not officially supported, but many robots like Googlebot are able to understand those easy wildcards. RegEx are definitely not supported. for additonal information

I guess what you are looking for is a robots.txt entry like this:

User-agent: *
Disallow: /www.example2.com

Let's suggestion you have more than 100 'parked' exampleNR.com URLs, but don't want to write a line for every single one of them...use this:

User-agent: *
Disallow: /www.example

The problem is, it actually is not officially supported, but many robots like Googlebot are able to understand those easy wildcards. RegEx are definitely not supported. for additonal information

UPDATE

Deleted the trailing asterisk since robots.txt uses simple prefix matching anyway. Thanks for your attention, w3dk