Maybe not at the moment. Its a journey I have often taken. It is multiple stages. Radyr to Cardiff Central, walk from platform 6/8 to platform 2, Cardiff Central to Bristol Temple Meads, Bristol Temple Meads Airport Bus Stop to Bristol Airport. Currently that is a single ticket.
I do not need to make point with this journey. Many people Radyr->Cardiff Central, Cardiff Central->London (PAD). Again this can be a single ticket, Transport for Wales from Radyr then GWR from Cardiff to London. I could buy this ticket from either company. It would need to be loaded onto one or other card. Can it be done? Does it work?