Re: Alton Towers | SW7 | Unknown (Gestlauer?) World's 1st
Coaster manufacturers use other people's products in their coasters all the time. So they could integrate in with another manufacturer if, say, Premier suddenly started selling the components for "twisting track".
They would buy those components in the say way they buy the sensors, PCBs, brake fins, etc, etc, etc from another supplier. I know it's been mentioned recently, but this is how Intamin and B&M worked for a short period of time, with Giovanola. They produced the actual coaster track for both companies, while Intamin and B&M essentially acted as analysts, consultants, designers and finally oversaw the ride assembly.
Giovanola took what they had learned and used for Intamin and B&M and set up on their own. I'm sure that if (I don't know if Giovanola are still about) B&M required track production in a hurry and couldn't do it at their own plants, they would still happily subcontract to Giovanola - it's just the way the industry works.
So yeah, there can be a degree of cross work between manufacturers on parts that one company may be able to do that another is lacking. However, it's rare and it would still just be "one component" of the whole and not a joint project.