SWIFT_PORT_UNAVAILABLE

Hi,
      is it possible that we get "SWIFT_PORT_UNAVAILABLE" in asterisk dial plan variable? like we can get DTMF value in ${SWIFT_DTMF}.

when all ports are in use then we get "SWIFT_PORT_UNAVAILABLE" in asterisk CLI then call hangs up.
if i can get "SWIFT_PORT_UNAVAILABLE" in variable then i can handle the call, instead of hangup

Thanks.