I had run into this issue a while back, when I had two Bitbucket accounts and wanted to had to store separate SSH keys for both. This is what worked for me.
I created two separate ssh configurations as follows.
Host personal.bitbucket.org
HostName bitbucket.org
User git
IdentityFile /Users/username/.ssh/personal
Host work.bitbucket.org
HostName bitbucket.org
User git
IdentityFile /Users/username/.ssh/work
Now when I had to clone a repository from my work account - the command was as follows.
git clone [email protected]:teamname/project.git
I had to modify this command to:
git clone git@**work**.bitbucket.org:teamname/project.git
Similarly the clone command from my personal account had to be modified to
git clone git@personal.bitbucket.org:name/personalproject.git
Refer this link for more information.