Import Protobuf types from other packages

Assuming we have 2 Dart packages.
Package `A` is a library. It defines Protobuf types and Dart utilities to work with them.
Package `B` depends on `A`. It also defines Protobuf types, which depend on types from `A`.

When trying to build `B`, we cannot avoid re-generating Dart code for Protobuf types is `A`. If we don't generate `A` types again, `B` types are generated with relative imports for `B` types and do not compile.
Is there a way to make the plugin use absolute imports and configure the mapping of imported types to the Dart packages which contain them?