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 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)