Is it possible to add multiple conditions to a Header directive with htaccess, e.g the following checks if a PDF has been requested and forces a download instead of opening in the browser.

SetEnvIf Request_URI "\.pdf$" requested_pdf=pdf
Header add Content-Disposition "attachment" env=requested_pdf
How can I modify this to only take this action when the User-Agent is IE? Can the variables set in the following be combined in the Header directive?

SetEnvIfNoCase User-Agent (Opera|Chrome|Version|Firefox|MSIE)[\/|\s](\d+)\. browser=$1 version=$2
SetEnvIf browser MSIE browser=IE