[olddustytrail]

There's an option in newer git. For cloning new repo:

git clone -c "core.sshCommand=ssh -i ~/.ssh/bitbucket-work -F /dev/null" [e-mail]:example/example

For existing repo:

git config core.sshCommand "ssh -i ~/.ssh/bitbucket-work -F /dev/null"

Where "bitbucket-work" is the name of the key for that particular repo.