Do you get a free rape after the 5th one, S@S? It's linear and transitive, right?
Think of how absurd and disgusting what you have written is. Each of those people contributed to the utter traumatisation of that girl. They should each be treated with the same punishment as one rapist. They all intended to do the same thing.
Nobody is in a position to judge the severity of a rape. Different people react to trauma differently. You'll find some remarkable cases of girls who have been raped consistently for 5 years and get over it with relative ease.
You'll find the majority of girls will be severely traumatised for the rest of their lives by any sexual assault.
We should not be handing out punishments based on individual reactions or it would vary from case to case even for the same crime. Would we hold up the example of the survivor who brushes it off without a second thought? When many suffer daily with the pain? Should we say that because she barely suffered that her attacker should not be punished? Or should we acknowledge that the action itself has such capacity to do such extraordinary harm that unilateral punishment is required wherever it surfaces.
Intent is what should be punished. These 5 people each intended to rape this girl, so they should all be equally tried for rape. There's really no logical argument here. The sentiment is disgusting that because there were more people they should share lesser punishments. How callous.