Unlike subnetsFromParameter, which preserves an unresolved deployment-time list, this returns
numSubnets individually addressable subnet references using Fn::Select. Use it when iterating
at synthesis time to create resources that each require a single subnet ID.
Defaults to three subnets; fewer parameter entries fail at deployment, and extra entries are ignored.
Unlike subnetsFromParameter, which preserves an unresolved deployment-time list, this returns numSubnets individually addressable subnet references using Fn::Select. Use it when iterating at synthesis time to create resources that each require a single subnet ID.
Defaults to three subnets; fewer parameter entries fail at deployment, and extra entries are ignored.