If you need multiple references in one in-text citation, you can accomplish this in one of two ways. One option is to insert all of the citations together:
To insert multiple citations:
Hold down the Command Ctrl key while clicking on the desired references in your library (or hold down the Shift key to select a continuous range of references).
From the Edit menu, select Copy.
Position the cursor in your word processing document where you want the citations, and select Paste from the Edit menu.
The citations are inserted together in one set of delimiters. Once formatted, they appear in one multiple citation, sorted as your bibliographic style requires:
Unformatted: {Hall, 1999 #90; Baker, 1988 #38}
Formatted: (Baker, 1988; Hall, 1999)
The other option is to add the citations to the paper individually. EndNote merges adjacent citations automatically during the formatting process. Citations do not merge, however, if any character, including spaces or punctuation, separates them.
Unformatted: {Hall, 1999 #90}{Baker, 1988 #38}
Merged when Formatted: (Baker, 1988; Hall, 1999)
Note: If one of the citations in a multiple citation cannot be matched during formatting, the entire citation will remain unformatted.