I agree with Elly. Just because species are similar doesn't mean they can, or will, interbreed. Litoria infrafrenata (White-Lipped) and Litoria caerulea (White's tree frog) have different needs, even though they overlap territory some in the wild, and are just different enough to where crossbreeding is very highly unlikely. In captivity it is not even recommended that different species be kept in the same enclosure together, much less make an attempt to interbreed them.