This is not currently possible unfortunately. You have to submit a specific directory for file scanning. Wildcard based file scanning is not currently possible. This feature is on our customer wish list, but we do not have a release date for it.
While this feature is not necessarily difficult to implement, we are investigating ways to lessen the impact it has on performance. These kinds of scans are extremely taxing on client machines and take a very long time to complete. That is why this functionality is not currently available.