>>530248859
For career mode, you're a different dude each time, as >>530248932
It's only in the main stories that (You) get to build a team (harem), but with the latest volume the team has that jockey connection.

Something they seem to be trending towards, as team IKZE (Orfevere, Curren Chan, Sweepy Tosho, Durandal, Dream Journey, Blast Onepiece), which share the same trainer across their campaigns.