No can do. Runtimes are specifically crippled to keep them from working as clients of a hosted database. They are strictly single user only unless you host it from FileMaker server and then it works like any other Filemaker file--clients need either FileMaker Pro or you publish to the web so that they can get to it via web browser.
So, with the Filemaker Server, can you use runtime solutions on each PC or does each PC have to have Filemaker?
You can put run time files on the server and then each PC uses FileMaker to access the file. The run time file gets hosted just like any other FileMaker file.
(If FileMaker allowed a run time to be a client, a lot of us developers wouldn't need to make volumne license purchases of FileMaker Pro for the client machines. They do have to make profit you know...)