Go to Version Sync in Project A (Classic: Project A > Project settings > Version Sync/ Next-gen: Project A > Project Settings > Apps > Version Sync)

  1. Click “Duplicate versions to a target project” on the top of the screen

  2. Select Project B as target project

  3. Save

  4. Note that current versions of Project A are displayed

  5. Save

With that configuration versions will be synced from Project A to Project B. But not from Project B to Project A.