Passing a $_GET variable from Wordpress page into external iFrame
Edit:
[iframe src="globaleye.com/external/refer.php?YOUR_VARIABLE=true"; width="100%" height="500"]
if you used more than one variable pass so you use an advanced iframe plugin so it is good for you.
[advanced_iframe securitykey="key" url_forward_parameter="SECOND_VARIABLE" src="globaleye.com/external/refer.php?YOUR_VARIABLE=true"]