Gatling switch protocols during scenario

I'm trying to create a Gatling scenario which requires switching the protocol to a different host during the test. The user journey is

https://example.com/page1
https://example.com/page2
https://accounts.example.com/signin
https://example.com/page3

so as part of a single scenario, I need to ether switch the protocol defined in the scenario set up, or switch the baseUrl defined on the protocol but I can't figure out how to do that.

A basic scenario might look like

package protocolexample

import io.gatling.core.Predef._
import io.gatling.http.Predef._

class Example extends Simulation {
  val exampleHttp = http.baseURL("https://example.com/")
  val exampleAccountsHttp = http.baseURL("https://accounts.example.com/")

  val scn = scenario("Signin")
    .exec(
      http("Page 1").get("/page1")
    )
    .exec(
      http("Page 2").get("/page2")
    )
    .exec(
      // This needs to be done against accounts.example.com
      http("Signin").get("/signin")
    )
    .exec(
      // Back to example.com
      http("Page 3").get("/page3")
    )

  setUp(
    scn.inject(
      atOnceUsers(3)
    ).protocols(exampleHttp)
  )
}

I just need to figure out how to ether switch the host or protocol for the 3rd step. I know I can create multiple scenarios but this needs to be a single user flow across multiple hosts.

I've tried directly using the other protocol

exec(
  // This needs to be done against accounts.example.com
  exampleAccountsHttp("Signin").get("/signin")
)

which results in

protocolexample/example.scala:19: type mismatch;
 found   : String("Signin")
 required: io.gatling.core.session.Session
       exampleAccountsHttp("Signin").get("/signin")

and also changing the base URL on the request

exec(
  // This needs to be done against accounts.example.com
  http("Signin").baseUrl("https://accounts.example.com/").get("/signin")
)

which results in

protocolexample/example.scala:19: value baseUrl is not a member of io.gatling.http.request.builder.Http

You can use an absolute URI (inclusive protocol) as a parameter for Http.get, Http.post and so on.

class Example extends Simulation {
  val exampleHttp = http.baseURL("https://example.com/")
  val scn = scenario("Signin")
    .exec(http("Page 1").get("/page1"))
    .exec(http("Page 2").get("/page2"))
    .exec(http("Signin").get("https://accounts.example.com/signin"))
    .exec(http("Page 3").get("/page3"))
  setUp(scn.inject(atOnceUsers(3))
    .protocols(exampleHttp))
}

see: https://gatling.io/docs/current/cheat-sheet/#http-protocol-urls-baseUrl (link is dead, wayback machine version: https://web.archive.org/web/20170915100135/http://gatling.io/docs/current/cheat-sheet/)

baseURL: Sets the base URL of all relative URLs of the scenario on which the configuration is applied.