TLDR: Can anyone tell me how to use pretest in mashup contest?

So in normal contest in codeforce, I saw that our submission was judged by the pretests, and when the contest is over, it will be rejudged by the main tests. So it's there a way to pretest submission in a mashup contest. Currently, I making a contest for my learning group in codeforce, and I want to use pretest in order to reduce judging time. Of course, I can just put only the pretests in the problems first, when the contest is over, I will upload the main test and manually rejudge all of the solution. This is my only method, but it's really inefficient. So, it's there better ways to do it?