How to configure a right click menu in the Finder to hidden for some special data type file?

Question

I have created a service for my OS X(10.7.3). And I have configure it in the info.plist like so:

<dict>
    <key>NSServices</key>
    <array>
        <dict>
            <key>NSMenuItem</key>
            <dict>
                <key>default</key>
                <string>Edit the file...</string>
            </dict>
            <key>NSMessage</key>
            <string>runWorkflowAsService</string>
            <key>NSRequiredContext</key>
            <dict>
                <key>NSApplicationIdentifier</key>
                <string>com.apple.finder</string>
            </dict>
            <key>NSSendFileTypes</key>
            <array>
                <string>public.item</string>
            </array>
        </dict>
    </array>
</dict>

And it will be visible for any "file and folder"(public.item) in the Finder, but I would like to make it invisible for some files with special data type(eg. *.txt, *.rar).

Is there any ways to configure the info.plist to accomplish it?