3 servers but 2 can't communicate (text...)

Hi,

     I ( would ) like to use Spread in a Wan (but i'm testing it on a 
lan) with the following configuration :

Spread_Segment  X.Y.Z.233:4803 {
         s1 X.Y.Z.233
}
Spread_Segment X.Y.Z..232:4803 {
         s2 X.Y.Z..232
}
Spread_Segment X.Y.Z..229:4803 {
         s3 X.Y.Z..229
}

     If I disable the link (using a firewall rule) between s1 and s2, 
then s1 or s2 leaves the group.

     Can I configure spread to use s3 as a relay between s1 and s2 or is 
there somethin wrong with my configuration ?

Regards
--
Fabrice