Simultaneous domain assignments

[GRA0007]

Hey, we have a monorepo with several Next.js projects that all depend on each other, and sometimes we do a deployment that will break one of these projects if they are not all updated together.

Some of our sites take longer to build than others, so currently when we do a deployment, some are swapped over to the new version before others, breaking any dependent functionality until all sites have finished deploying.

I propose that Vercel offer a feature to wait after building a site until all projects in that monorepo have finished building, before moving them all to the domain assignment step simultaneously. This would prevent downtime for users who happen to visit one of our sites while in a partially deployed status.