There can be only one SSL enabled site per ip, but that is already clear as I understand from your last post.
The thing with SSL is that there is no hostname, just ip-number. The hostname is not visible to apache. Therefore if
point to the same ip number and you have enabled SSL on domainone.com a request to https://www.domainone.com
should go to the same site whereas http requests will go to the two different sites.
In SSL only ip number counts.