Upcoming neutrino telescopes may discover ultra-high-energy (UHE) cosmic neutrinos, with energies beyond 100 PeV, in the next 10-20 years. Finding their sources would identify guaranteed sites of interaction UHE rays, whose origin is unknown. We search for by looking multiplets neutrinos arriving from similar directions. Our forecasts are state-of-the-art, geared at radio-detection IceCube-Gen2...