Unfortunately a FileMaker Runtime solution does not have network capabilities, so you cannot share a single runtime or the data to multiple users, you can use FileMaker Server to host the runtime but then each user will need a copy of FileMaker to access it.
One option for you would be to look into using IWP, or custom web publishing. With IWP you host the file using a copy of client or Server adn the users access the same source via there web browser.
IWP is a cut down version, an there may be some tweaking to be made to your layouts and scripts, but would allow you to get a number of users up and running without a copy of client fairly quickly.
I hope this helps.
One of my customers puts the run time application on a shared drive. Anyone with access to the shared drive can then access it but only one person at a time.
This is a solution. But without network co-operation, it means little in an office environment.