http://www.pbxnsipsupport.com/index.php?_m...kbarticleid=506
is this for my situation? ""Loop-Start" indicates the beginning of the list of extensions per device. You may provide two optional parameters for this tag. The first parameter indicates the number for the first entry (typically, "0" or "1"). The second parameter indicates the maximum number for the loop. This way, you can avoid providing too many extensions for the phone. For example, if you want to have only two extensions with the index 1 and 2, you would use the tag "{Loop-Start 1 3}". "