Caste discrimination in the US manifests more as social "discrimination", where people from a caste lean towards others from the same caste than others due to perceived brotherhood. I feel like this especially manifests in groups where there are already a large number of Indians, such that being Indian itself isn't enough brotherhood. Eg, when choosing between two equally qualified Indians, choosing the person from the same caste (which is slightly ironic since a similar idea applies to diversity initiatives).

As another commenter said, it's a sort of "fractal" discrimination.