Travel to Dhaka -Vancouver-Toronto-Dhaka by China Southern Airline

Hi,
Our transit will be through Guangzhou airport. On return we want to go to Beijing by air and to visit for 48 hours there. Thereafter we will return to Guangzhou by air and back to home. all travel will be by china southern airlines. As Bangladesh nationals is it possible to get a transit G as mentioned above.
thanking
Pradip Kr Das