Quiz

Hi Claudio,
it has nothing to do with your English level - I just needed more details to understand your scenario
There might be different ways to achieve what you need:

1. create in the course 5 identical quizzes and make each quiz visible only to a group and available the dates you want to. One disadvantage of this approach is that the results are not collected into one single quiz and you might need this kind of analysis.
2. create a single quiz and make it available for the corresponding group depending on the date, i.e. if Group 1 has to complete it in September, you make it available only for Group 01. Then in February, you have to remember to add /to change the restriction and add also Group 2, etc. 

There are probably other approaches but these are the first that I can think of.