Can a github repo with gems that can't be bundled provide gems that can be bundled?

I have a rails project where a private repo is used to provide several gems, as the bundler docs describe ie I have a block like

git 'http://ift.tt/29sphg8' do gem 'a_nice_gem' gem 'a_silly_gem' gem 'a_much_needed_gem' end

in my Gemfile.

The repo, private.git, contains a gem bad_gem with an incorrectly formatted .gemspec, for instance, or bad dependencies. Bundling the project errors out, despite bad_gem not being a dependency.

Is there some way to make bundling my rails app succeed without fixing bad_gem?