Okay, I just went looking for it and found at least the search can be done in gmail in two clicks as well: Right click an email, pick "Find emails from ...." near the bottom of gmail's custom menu. It doesn't have the "in:inbox" part of the search but presumably that's not much an issue since new emails would be at the top and gmail does display tags (including "Inbox") next to the subject line.
I tried this before, it doesn't handle group emails correctly. Google groups is one of the official methods recommended by Google to have a shared inbox and this filter automatically selects all emails sent to the group's address rather than by sender.
