There is no way to work as a bartender since it is an utter and direct partnership in crime, according to Rabbi Yuval Sherlo, head of the Petah Tikva hesder yeshiva.
In the Q&A; section of the Moreshet website, one of the surfers wrote Rabbi Sherlo, "I have a question whose mere arising embarrasses me. I know that the profession of a 'barman' (a server of beverages in a bar) is not a fitting profession for someone who abides by the Torah and Mitzvot. And yet, for a person who was hired to work as a barman, aside from the many prohibitions (a place of immorality, etc.), there is the problem of serving wine which is not always kosher.
"For some reason, this is a transgression that worries me more. Am I committing a direct crime by serving potentially non-kosher wine and beverages? Again, I apologize for the question. It seems as if I am asking how to kosher a knife in order to slaughter a pig."
"I can't find a way in which someone can be a barman due to various reasons," answered Rabbi Sherlo in his extensive answer. "This issue derives from an unmistakable partnership with a direct crime."