Extracting the date that a Group member last signed a document

I have a requirement to extract the date that a package was completed. As we have signing Groups who sign in a particular order, I can extract the date that the last known group signed by retrieving the SignersCompletionReport (through esl.ReportService.DownloadCompletionReport = yields => SenderCompletionReport =yields=> PackageCompletionReport =yields=> SignerCompletionReport) But we have groups defined, call them Group1 and Group2 I find that the SignersCompletionReport does not give the actual member of the group that signed but it will return a structure like this What I get: email: [email protected] firstname: Group1 id: 9cbe375c-bafe-4a71-bdc4-24d3f8a60888 The "id" property is a totally random guid I do not recognize. The "email" property contains the Group1 ID GUID (fea96...), which I do recognize, but I now need to parse that fake email format to get the actual Group guid. What I expected: email: blablaperson@memberthatactuallysigned_andbelongstogroup.com firstname: Bla Bla first name id: fea96302-8e3d-43a9-8882-e28cb73e4b92 = Would be nice if this were the actual group ID or there was a property with the group ID So now I need to parse the faux email address to extract the group id: That makes no sense to me on some level as we have an apparently Globally Unique ID which is encoded in an email which might or might not be unique. Question: Can I rely on this email format being consistent? (*@groups.esignlive.com) With consistent I also mean if the solution is switched to the non-sandbox / production environment will those emails still look the same? Does that group identifier change depending on where the group is created? (Api creation vs. UI console creation)