Warp Teleport with Apple Watch Companion International travel

I’m on the unlimited premium with warp and companion Apple Watch. I have multi network with dark star setup. Content with this for 99% of what I do. Question is on roaming. Lightspeed and dark star are far better for international roaming. If I teleport my main line to one of those what happens to my Apple Watch? Does service just stop? What happens when I get back home and teleport back to warp? Also, how much would it cost to just have my MUlti network line be by international main line? I.e. put all my roaming though that while I travel and then when I come home my primary is never impacted? If I have to pay for it that’s fine.