I noticed that I can leverage Shared Activities on outbound emails from Salesforce, but it seems like Email to Salesforce doesn't seem to support it. Was curious if anyone had a good workaround on implementing it -- would a trigger capture the entire batch of users in the "TO" field and let you write code to compact 3 emails into one activity? Any ideas?
Salesforce delivered this natively back in the Summer 13 Release.
https://success.salesforce.com/ideaView?id=08730000000hqc7AAA
Prior to that, we wrote a trigger on Task to determine if it was an email, and if so manually parse through the To/From fields and associating with Contacts with matching emails in the system.