After noticing the men were wearing kippot, the gang "started using antisemitic slurs and started to push us out of the building. That was when it started getting violent".
Mr Roiter-Jesner, a politics student, said he was also pushed by the attackers, who were "saying 'dirty Jews, you don't belong here', 'Jews get out of here', along with stuff like 'we'll bash your faces in' and 'get the f*** out of here'".
He complained to the bar following the incident on October 28 and was told the venue had been hired by two Christ's College sporting societies.
When Mr Roiter-Jesner then wrote to Jane Stapleton, Christ's College master, she replied saying she condemned antisemitism and would investigate.
After waiting for a further response, the 25-year-old was told two students had been identified and disciplinary action taken.
But Mr Roiter-Jesner and his two friends were not asked to give evidence during the Christ's College investigation, leading them to describe the probe as "a cover up".
His friend said: "They refused to accept the fact this incident was antisemitic in nature."
The unnamed victim claimed college sources had told the Jewish group the attackers' punishment had been "a slap on the wrist, what you would expect for a little bit of drunken pushing".
The students now plan to take their case to higher authorities at Cambridge.
Mr Roiter-Jesner said: "We would like a senior member of the university to review the punishment meted out and make sure it is appropriate and in line with our accusation."
He said that, while the victims understood the college had been unable to corroborate their accusation of antisemitism, the students felt their claims of Jew-hate had been "undermined", warranting a "public apology".
In a statement issued by Prof Stapleton to college alumni last weekend when the Jewish students' allegations came to light, she wrote: "The college understood that the complainants had provided us with their complete account of the incident and did not request at any stage to be interviewed further."
Prof Stapleton added: "Two Christ's students admitted using foul language and participating in a scuffle but they denied initiating the physical hostility and denied using any antisemitic or racist language. In relation to the former they were disciplined."
In another letter to students and staff sent on Sunday, Prof Stapleton condemned antisemitism and said "uncompromising disciplinary action would be taken if any substantiated evidence comes to light that a member of Christ's engaged in such conduct".
She said there was "no corroborating evidence" of antisemitism during the incident.
Mr Roiter-Jesner and his companion have reported the incident to the police.
A Cambridgeshire Police spokeswoman confirmed officers had been contacted on Tuesday with details of a "racially-motivated" incident. She asked for anyone with information to get in touch with police.
A Cambridge University spokesperson said it would be inappropriate for the university to comment while officers are investigating.
