I am unable to create multiple BitBucket accounts. [Mac]

[fbartram]

I have a personal account on BitBucket and want to add a second account for work. I have been given a SSH key-pair for use and have created appropriate id_rsa.<username> files and edited my ~/.ssh/config file. From the Terminal, ssh works as expected and I am able to connect with BitBucket.

When I try to "add" a new SSH account to BitBucket, SourceTree is using the wrong id_rsa files. Is there a way to make SourceTree use specific id_rsa files rather than the default pair?

Thanks for any tips.