Between group contrasts and graph theory

Hello Conn community,
I am setting up the contrast portion of my analysis and wanted to confirm that I'm on the right track. In my analysis, I have four levels of my variable of interest (body mass index). The goal is to examine local and global efficiency within networks of selected ROIs, and detect between-group differences therein.
What I would like to see is how group membership affects these properties at the network level and then work backwards identifying group differences at the nodal level. At this point, I've set up an initial contrast [1 0 0 0; 0 1 0 0; 0 0 1 0; 0 0 0 1] which is looking for any effect of group membership on these properties. I've attached an image of the output. My interpretation of the output is that there is a significant effect of group membership on local efficiency at the network and nodal level. But I can't decipher how to obtain further information as to where these differences lie in terms of membership or in what direction. Is there an omnibus way to do this? Or should I structure specific contrasts?
Many thanks for your time and help!