You can pick your route which will impact where you start. Even if you're riding the alpe, they give you a 15-20min run in on rolling terrain

You can get down to about 6 or 7 for the Alpe if you start on the Jungle circuit.
It took me about 20 climbs to get the Meilensteins...

I’m pretty sure that for any course you pick, you will always spawn at the same place. So no, you do not get to pick where you start on the course you select.

As others have said, you can't pick where you start - it's pre-defined based on the route you select. That said, if you want more of a warmup before hitting a particular climb you can always hang a u-turn and tack on a few extra miles, then turn around and head for the climb.

You used to be able to click on the name of another Zwifter and you would spawn next to them to start your ride. Haven't tried to do that in over a year, so I don't even know if it's still something you can do.

---

''The enemy isn't conservatism. The enemy isn't liberalism. The enemy is bulls**t.''

—Lars-Erik Nelson

I think you’re right. If someone is on your friends list, then you can click on him or her, and spawn next to them.

If only you could see the number of similar requests for this and custom routes on the Zwift forums 😂😂