We construct multi-black hole solutions in the five-dimensional
Einstein-Maxwell theory with a positive cosmological constant on the
Eguchi-Hanson space, which is an asymptotically locally Euclidean space. The
solutions describe the physical process such that two black holes with the
topology of S^3 coalesce into a single black hole with the topology of the lens
space L(2;1)=S^3/Z_2. We discuss how the area of the single black hole after
the coalescence depends on the topology of the horizon.Comment: 10 pages, Some comments are added. to be published as a letter in
Classical and Quantum Gravit