The court, however, acquitted TV journalist Gaurav Jyoti Neog, who had been accused of inciting the crowd to molest the girl, and three others.
"Today's judgment has proved that the channel did not instigate the molestation," Neog said after the verdict.
The Kamrup chief judicial magistrate's court sentenced the men - including main accused Amarjyoti Kalita - to two years' rigorous imprisonment and a fine of Rs. 2,000 each.
Kalita, the prime accused, had initially eluded the investigators, but was later arrested from Varanasi.
An employee of Assam government's IT agency AMTRON, he was sacked after his role in the case came to light.
His counsel said they would challenge the verdict in the district and sessions court. Three others were acquitted for lack of evidence.
The case against a fifth - a minor - is being heard in the juvenile justice court.