Problems multihosting multi subdomains

Hi everybody !!

I have a domain and subdomains which are not managed by dreamhost.
The domain pointed to a webhosting that is not managed by dreamhost. But I want 2 of my subdomains to point to 2 directories in my webdhosting managed by dreamhost.

My domain is managed by Gandhi.
My dreamhost webhosting is Crazy Domain Insane.

How can I do this ?
Thanks in advance