Try
KE4EST, he might have a supply.

I have the HD-RE, the previous model and it would do what you need, but I think those are likely all gone.
Another option is a PCI-card or USB receiver, but those are much more complex to deal with because then you are dealing with various softwares to read the signals.
Not sure on your Lexion for scanning particular transponders, maybe try "satellite scan" and see if there is an option to scan particular TPs. If you already have the transponders in the list there would not be a need to add anything or blind-scan.