Unlike Oyster, you usually can't load "money" into ITSO cards. In Southampton you can load "journeys" or "season tickets" and I think the same in Bingley. I put journeys on my Southampton card because I don't use a bus for weeks at a time. But you do that by going to a web site with ID for the local card, there's no way that I've found to go "Er, I have a different ITSO card from somewhere else".