I think that there are some distinct similarities and differences between Dante's conception of hell and Sartre's vision of the underworld. On one hand, both would agree that the actions of other people is what makes hell. Sartre looks at it as the manner in which human beings interact with one another. The personal cruelty that human beings inflict on one another is what Sartre makes clear is hell. At the same time, Dante's vision of hell is filled with the resultant actions of other people. Dante makes clear that both sins and the sinners are punished, proving that hell is filled with "people." For both, human action is the reason for hell.
The primary difference where I am not sure there is anything in way of reconciliation is the belief in how hell is constructed. Dante's vision of hell is one where sinners against God is punished. The primary construction base for this hell is one where God is present. The transcendental vision of God is what makes Dante's hell. This is why people are in hell and why sinners are punished. God's redemption and need to punish is what makes hell. As an existentialist, Sartre would reject this. The main reason why hell is consisting of "other people" is because of Sartre's belief that there is no God or transcendental deity that provides totality. Hell has to be other people because there is no one else in Sartre's mind. The result of individuals being cruel to one another is the only reality for Sartre that can construct his vision of hell. The rejection of totality is what makes hell "other people" for Sartre, something that Dante could not accept as it violates his fundamental premise for both his vision of hell and the redemption that follows.