The scenario is
Folder F1 contains Project P1 with VPCSC perimeter_1. Can I have another Project P2 with VPCSC perimeter_2 under Folder F1?
In other words, Can a folder contain Multiple VPCSC? Or what is scope of VPCSC - Project or Folder?
Yes, you can have another project P2 with VPCSC perimeter_2 under Folder F1 while Project P1 has VPCSC perimeter_1. The folder itself does not impose constraints on the VPCSC configuration of the projects it contains. Each project is independent in terms of its VPCSC perimeter.