Another phrase for "dealing with people you wouldn't normally want to deal with but you do"

Has anyone got a nice phrase for "dealing with people you wouldn't normally want to deal with but you do because they perform a function that you would not want to do or are not able to do"?

I have in mind the situation in the Merchant in Venice where the Venetians tolerate the Jews, even though they dislike them, because they need them as moneylenders, since Christians were officially not allowed by the Church to collect interest (this despite the fact that countless Christian countries, including Venice, had commercial banks with networks operating all over Europe by the early Renaissance).

"Necessary evil" is a common description for unpleasant people or things that one is forced to deal with.

An opportunist deals with people by the maxim the end justifies the means: he will use people or parties as a means to whatever his goals are, sometimes disregarding ethical concerns. He may form a coalition with liberals even though he is a socialist himself, if this coalition furthers his goals in some way. You might also call him a Machiavellian, though this implies an even more ruthless application of the maxim.

There is also modus vivendi: a situation in which several parties coexist more or less peacefully, not because they like each other or feel the situation is optimal, but rather because destroying the equilibrium by attacking or leaving the system would worsen their own position too much. This situation is less benign than a symbiosis, in which both parties not only profit from each other but are usually also fully committed to each other.

Man, i know the damn thing in Hindi but a word by word translation in English would be "If need be, call an ass a Father"