The environments feature is useful, but I'd like to be able to tie environment groups to environments, thus allowing each env to have an "instance" of an env var group. For example, if I define a blueprint for a service and assign it the "postgres" env var group, I would be able to assign different env var values in this group for both my staging and production environments. The same kind of logic could potentially also apply to preview environments. Currently we are working around this by having a copy of each env var group for "prod" and "staging", but better integration with the new environments feature would make this really neat.
