Go to Version Sync in Project A:

Company-managed: Project A > Project settings > Version Sync
Team-managed: Project A > Project Settings > Apps > Version Sync

  1. Create new group “PA” with default settings

  2. Go to Version Sync in Project B

  3. Select the group “PA” 

  4. Select the desired outcome for synchronization

  5. Save

  6. If applicable sync existing versions from Project B manually

Future version will be synced automatically.