¿Quiere iniciar dnsmasq ony cuando Thunderbolt Ethernet está activo?

dnsmasq se instala utilizando homebrew. Actualmente dnsmasq está enviando spam a mi system.log con mensajes como este:

Sep 26 18:22:46 Laptop com.apple.xpc.launchd[1] (homebrew.mxcl.dnsmasq[14526]): Service exited with abnormal code: 2
Sep 26 18:22:46 Laptop com.apple.xpc.launchd[1] (homebrew.mxcl.dnsmasq): Service only ran for 0 seconds. Pushing respawn out by 10 seconds.
Sep 26 18:22:56 Laptop com.apple.xpc.launchd[1] (homebrew.mxcl.dnsmasq[14527]): Service exited with abnormal code: 2
Sep 26 18:22:56 Laptop com.apple.xpc.launchd[1] (homebrew.mxcl.dnsmasq): Service only ran for 0 seconds. Pushing respawn out by 10 seconds.
Sep 26 18:23:06 Laptop com.apple.xpc.launchd[1] (homebrew.mxcl.dnsmasq[14528]): Service exited with abnormal code: 2
Sep 26 18:23:06 Laptop com.apple.xpc.launchd[1] (homebrew.mxcl.dnsmasq): Service only ran for 0 seconds. Pushing respawn out by 10 seconds.
Sep 26 18:23:16 Laptop com.apple.xpc.launchd[1] (homebrew.mxcl.dnsmasq[14529]): Service exited with abnormal code: 2
Sep 26 18:23:16 Laptop com.apple.xpc.launchd[1] (homebrew.mxcl.dnsmasq): Service only ran for 0 seconds. Pushing respawn out by 10 seconds.

porque le dije a dnsmasq que usara solo el adaptador Ethernet Thunderbolt y cuando este adaptador no está activo, dnsmasq no puede encontrarlo, por lo que no puede iniciar el servicio.

Quiero ejecutar el servicio dnsmasq SOLAMENTE cuando el adaptador Ethernet Thunderbolt está activo. NO PUEDO ejecutarlo en todas las interfaces.

Mi lista actual se ve así:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
  <dict>
    <key>Label</key>
    <string>homebrew.mxcl.dnsmasq</string>
    <key>ProgramArguments</key>
    <array>
      <string>/usr/local/opt/dnsmasq/sbin/dnsmasq</string>
      <string>--keep-in-foreground</string>
      <string>-C</string>
      <string>/usr/local/etc/dnsmasq.conf</string>
    </array>
    <key>Requires</key>
    <array>
      <string>Network</string>
    </array>
    <key>RunAtLoad</key>
    <true/>
    <key>KeepAlive</key>
    <true/>
  </dict>
</plist>

No puedo encontrar ninguna documentación sobre cómo iniciar dnsmasq SOLAMENTE cuando cierto adaptador de red está activo. ¿Alguna idea?