Until/if that becomes available:
If you make one Asana project where each task represents one of your own projects, then you can use the task dependency feature to indicate your project dependencies and see them on a “projects timeline” which is effectively what that one Asana project’s timeline will be in this case.
I have a custom solution referred to in https://forum.asana.com/t/okr-tracking-in-asana/127/9 that uses multiple linked Asana projects for a powerful, flexible related solution.
Larry