Map domains that include a path

Hi,

I am trying to use this plugin with a subdomain multisite install hosted at http://www.multi-install.com and a set of custom domains, all including “/blog” in their paths.
The goal is to have the following custom domains mapped to point at their corresponding blogs on my http://www.multi-install.com WordPress, such as:

http://www.example1.com/blog -> example1.multi-install.com
http://www.example2.com/blog -> example2.multi-install.com

They work with simple domain names, but not with “/blog” in the URL.

Can this be achieved with the MU Domain Mapping and a subdomain network install? If not, what would be the correct setup?

Note: content for each custom domain “example1.com”, “example2.com” comes from another server different than the wordpress install.

https://ww.wp.xz.cn/plugins/wordpress-mu-domain-mapping/