How to set a limit to files that spark clients share

Hello people I send a letter to Winsrev but he didn’t answer yet any one of you could help me, I am implementing instantant messenger service in my organization I have from server side openfire 3.6.4 and clients spark 2.5.8 and 2.6.0 Beta2. I think is not good idea that the users share files without a limit. Here are my questions.

1. I would like to know if it is possible to set a limit size to files that share spark clients. How I could do that?

2. If the answer is not to the 1st question when we will have a version that include that or you have any idea on how I could solve this problem.

Jabtoledo