[Spread-users] Are all group messages sent to all servers?

[Jim Kleckner]

My apologies if this has been answered before.
My quick re-read of the user manual chapter 1
didn't reveal the answer.

My  recollection from long ago was that
messages to a group would only go to
those servers that have clients joined to
that group.  Someone made a comment
in the last few months that prompted me
to check that. 

Is spread clever about which messages
are sent to servers on different segments
such that they are sent only if that server
has more than 0 members of that group?

Presumably the special case of a message to
a private group is optimized this way, yes?

Thanks - Jim