Smith et al (2000,2002) etc. How to?

Hi, I am having a problem regarding in-text citation. I want to insert two citations with same first author, but different other authors. Example, (John A et al., 2000, 2002b). However, endnote shows that it can only be done when authors are same (John A and Smith B, 2000, 2002b). One journal wants the previous type of citation. Is there any workaround?

yes, to right click edit citation and to hide the authors of the second one, if it is the correct form for the first, or to hide both  and type what you want in the prefix box of the first.  It is highly unusual to use Smith et all for a two author paper though.