Use Composer
Put every bundle that needs to be shared between multiple projects in it's own repository, and use Composer to manage your dependencies (which are the bundles, because your main project depends on them).
As your bundles are probably private, and not meant to be reused by others, you don't want to add them to Packagist. Instead, you can reference the SVN repository directly:
Your main project's composer.json
:
{
"require": {
"vendor/my-private-repo": "dev-master"
},
"repositories": [
{
"type": "vcs",
"url": "git@bitbucket.org:vendor/my-private-repo.git"
}
]
}
See the Composer documentation for more information.