Kifaru Bwana is right Vishnu is going nowhere. The SSP tends not to break up breeding pair until they have had a number of calves. Two is hardly the tipping point. Even if the SSP wants to mix up the breeding since Vishnu is property of Toronto it's more likely Asha would go.
Cross border transfers has long been an issue. What the AZA tries to do is get a healthy population going in Canada, usually located at Toronto, Calgary, Granby, Vancouver, Edmonton and Winnipeg. They then let the population breeding until its time to bring in new blood. Any offspring that can be sent south is as soon as possible but they keep a couple up here for breeding. The other CAZA zoos are good in that they can hold surplus until the AZA needs them for breeding in the US. Plus CAZA zoos can also apply as non member participants to SSP programs and a number of them do participate in a few. The border doesn't pose much of a problem for many species but hoofstock and primates are always a problem.