\begin{table}%t2
 %\centering
\par
  \caption {Main parameters for the groups candidates for our fields. Their identification codes show
the average positions of the members. Mean redshifts~($z$) and average deviations  
are shown as velocities~($\sigma$). The biweight estimators
were used only in groups with at least 8~members. The group number identify  member galaxies in the 
online table.\label{T:groups}}
 \begin{tabular}{ccccl}
 \hline\hline
 Group &   ID              &  $\avg{z}$  & $\sigma$            &  $N$    \\
               &                                   &                       &  
               [km~s$^{-1}$] &              \\ \hline
1 & \object{r220\_1J 172604+742830}    &  0.053          &  126                     &  4          \\
2 & \object{r220\_2J 172518+742844}    &  0.043          &  390                     &  6          \\
3 & \object{r220\_3J 172958+744204}    &  0.243          &  401                     &  8 (11)  \\
4  &  \object{r265\_1J 131030+322840}    &  0.186         &  349                     &  7           \\ \hline
 \end{tabular}
 \end{table}