custom domain repo url without user name

Hello,

I have setup a custom domain "source.mydomain.com" with CNAME to bitbucket.org.

This works fine except, accessing the repositories using ssh requires to include the username: e.g.
{{{
git clone git@source.mydomain.com/MYLOGIN/testrepo.git
}}}

Is there a way to use a "portable" URL without the user name?
Something like this (note the missing MYLOGIN):
{{{
git clone git@source.mydomain.com/testrepo.git
}}}

Regards