Display Group Option in ABAQUS

Hi everyone

can anyone tell me how to use "display group" option in ABAQUS.

i have to find the total reaction force of set of all nodes on a particular surface. i had tried many times using "display group" option. but couldnt succeded.

or is there any other option to get the data from those set of nodes on a surface.  we have this kind of option in ANSYS, but what will the corresponding feature in ABAQUS.

Please help me in this regard. 

cheers

Ravitej