Posting in the Magento forums has been disabled pending the implementation of a new and improved forum solution which should better serve the community.
For new questions please post at magento.stackexchange.com, the community-run support site for the Magento community. We will be providing updates on the new forum solution soon. For questions or concerns please email email@example.com.
Multiple magento set-ups/site under one domain/server with a single checkout page
You could check out our multivendor solution for Magento, which could help you to set up multi store on your site and then when customer check out , they will be redirected in one check out page. Feel free to visit our blog for more info: