Due to updates that were made in the last few days to the S2 core, it is now possible. On the FriendsPage class, there are three new variables:
filter_active- A bool variable. The value is True if a filter is being used, False otherwise.
filter_name- A string variable. The value is the name of the filter if one is being used, empty otherwise.
friends_mode- A string variable. The value is "friendsfriends" if viewing the Friends' Friends page, empty otherwise.
Happy Coding everyone!