Bus travel in Cardiff

Kido

I'm going to be staying in Castleton on the outskirts of Cardiff. I see that Cardiff bus do weekly tickets, but the bus route I'll be using is operated jointly by Cardiff bus and Stagecoach. Am I right in thinking that I'll just have to time it right to make sure I get a Cardiff Bus or is there a weekly ticket I can get that will cover me on both? I'll be travelling into Cardiff most days and then in and around in afternoons and evenings.