The biggest question might be why you separate the administrative side outside of the 'Blog-Scope'. An administrative Module should only be the front-end to gather all backend-options (if that makes any sense)
However to get back into your question: you can simply include those classes from model A into model B, like use Blog\Model\BlogTable
Ultimately though i see management of a module as a responsible of the Blog-Module itself, as hinted within the first paragraph.
Edit: One thing i forgot to mention. Ideally if you decide to go the dependant approach, your module should make the BlogTable accessible through a service. That way your ModuleAdmin only has to do something like $serviceLocator->get('my-blog-table')
which is a much more clean approach.