That sent my cable OCD trough the roof.
Chopping the hoses has been explained enough. Now, to route it around the bottom bracket, and without seeing how exactly it works in your frame, the easy solution would be to leave a guide as you remove the old hose, then using that to yank the new one back to place. The Park Tool internal routing kit have something you can use, or you can try to improvise a way. Depends on how annoying is to go around the BB and how tiny are the holes really.
That sent my cable OCD trough the roof.
Chopping the hoses has been explained enough. Now, to route it around the bottom bracket, and without seeing how exactly it works in your frame, the easy solution would be to leave a guide as you remove the old hose, then using that to yank the new one back to place. The Park Tool internal routing kit have something you can use, or you can try to improvise a way. Depends on how annoying is to go around the BB and how tiny are the holes really.