You have to assume that the Indians know one another's tribal affiliation, otherwise the problem has no solution.
This problem is a specific instance of a generic truth teller/liar problem. I alluded to one of the others in my comment above about free beer in the city. In that case you only had one person to ask the question of and had to determine, not the status of the person you asked the question of but which road was the road to the city. In milum's problem, milum's solution, asking if the person's feet were green, satifies any possible interpretation of the problem from the original, poorly stated (and done so because it was being dredged up from the memory of what appears to have been a night when it was rather drunk out) statement of the problem. It also meets the criterion normally used in these problems, but not stated in this case, that the questions be yes/no questions.
