Hi @Marta_Bondyra,
Thank you for your response, I will try to do that in TSVB but i need to take my time to figure out how it works 
However, I already thought about creating a scripted field (that was my first idea) but my superior told me that i have to avoid scripted field because it would take a lot of space...
Thank you agin. I will share my graph once done with it in TSVB !