I don’t think you can, if the style requires semi-colons between different citations. If all of them should be commas, then the separation character is in the output style (see image attached).
A workaround is to hide the other authors and year, and type in the years, but that is annoying.
I let the publishers fix it, at the end of the day, if they have a house style that requires it. Most are used to Endnote user’s and the minor limitations imposed by automated software.
sorry – editing this incorrect reply – see next post.
