Can anyone tell me...?

Does the obligation to eat no meat on Friday's include broth, or food prepared with broth? I have guests coming to dinner tomorrow night, and they are not Papists, and also dislike seafod and cheese. This was unknown to me when we agreed on the arrangements, so now I am trying to plan a menu that is appealing to them and still meets my obligations. In particular, I was thinking of making a recipe involving Polenta, but I don't know if the chicken broth in the preparation is perfectly fine, a bit of a cheat, or verboten. Thank you for your help.