This is an office environment and while we all have iPhones and would like to use Remote with the Apple TV we don't want to all use the same Home Sharing account to do so.
You can't (yet)
Currently, the official Apple page:
Doesn't make any indication of how to do this. Neither does a quick Google search.
This Monday (June 10), Apple is expected to unveil iOS 7. There might be some changes there that accomplish what you want!
The AppleTV 2 is more flexible via Seas0nPass etc. I'd imagine if you went the route of jailbreaking, you'd get a favorable solution.
For example you could use several different third party wireless keyboards or mice. Doesn't exactly help with your current remote or your question, but thought I'd offer an alternative option that works for many people.