How to use Jenkins to manage a repository from Github with a submodule from Bitbucket?

For my Jenkins build, I need to manage a Github repository to automate building a project. However, the issue is that this repository needs to pull a submodule from Bitbucket. This requires two difference instances of authentication, one for each service. As of now, Jenkins is only allowing the use of a single set of credentials, using a username and SSH key. Is there a way to specify a different set of credentials for each pull?