merging data .foam file into one data array for plots

I am a bit new to Paraview and i am not very good with it, i have through simsale a .foam file with my results, now i have my wall regions selected and loaded with the data array that i want to plot, now only all the regions still have thier own arrays and i want to make it into one array in the picture is the line i want to achieve but i also want them to be grouped under 1 name and also with only one colour.