Two (or more) works with same date

Now I have 2-3 works with the same date, say (Jones 2010). In my former bibliographical program, when a second work with the same date was added, it would automatically add a letter, e.g. 2010a, so that the reader would know exactly which work by Jones in 2010 is referred to. How do I do that in Endnote X5?

For my bibliography, the style I use in the X5 program, I use a version of the Journal of Biblical Literature updated by Endnote techs. In Word 2010 I use the footnotesI use Tyndale (author-date). I have trouble imagining that every style would not use a way to automatically distinguish dates. I am uncertain how to attach my style file here.

I have several works by a single author with the same date. I want Endnote X5 to distinguish the datyes such as 2010, 2010a, etc.

Here is my Journal of Biblical Literature style revised by Endnote staff (renamed by me). However this format does nmot need to distinguish dates, since it calls for distinguishing information in footnotes. In the book I am writing now I use JBL style for bibliography (no need to differentiate dates); however  in the text I use Tyndale (author-date). Here I do have to distinguish between same dates.

JBL_final Copy.ens (55.2 KB)