跨域以使用cookie发布数据

I'm setting a PHP server that post data to another domain. This action is simulate user login and post status for update report status. But I have the following problems:

  1. After user login, it will response a cookies for next step update report status. How can I get the cookies in server?

  2. I want to done those procedure in my server, so that the connect is: Clinic device -> my server -> target server

Is it possible to prevent the clinic devices direct connect target server?

Is anyone able to help?