Hello Jorge, A soon as release 4.19 is launched, the feature of Domain VPCs(https://github.com/apache/cloudstack/pull/7153) will be available, which will allow users and operators to create tiers to VPCs for any account (or in your case project) to which the VPC owner has access, regardless of domain, thus, allowing all the projects to share a single VR.
For now, this feature is not available in the GUI; however, you can create a tier through the API 'createNetwork', informing both the projectId and vpcId. This feature has been tested using accounts, but not projects, so I will run some tests in the next few days and give you an answer regarding its viability. Kind regards, GaOrtiga PS: This email will probably be a duplicate since I tried sending it through a different provider, but it took too long, so I am sending this again to save time.
