Distinguishing multiple attachments

Content

I have a requirement to attach multiple files to an interview, very similar to Karthik Jayachandran's question http://communities.rightnow.com/comment/78632

The additional requirement I have is that it must be possible to tell which file has been uploaded to each control - ie I want the interviewee to attach document A and document B, then when reviewing the incident in the service cloud, the agent must be able to tell which attachment is A and which is B. We cannot rely on a consistent naming convention from the interviewee.

I haven't found any way of sending additional metadata with an attachment, and I wanted to see if anyone had encountered a similar requirement, or had any relevant knowledge to share