Per summary, the Cloud Network Summary page should show the ems_ref id.
For AWS, at least, this seems to be the only unique key and thus what would be used programatically.
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.
https://access.redhat.com/errata/RHSA-2018:0380