begin{tabular}{!{color{black}vrule}c!{color{gray}vrule}c!{color{gray}vrule}c!{color{black}vrule}}
    arrayrulecolor{black}hline
    & & \
    arrayrulecolor{gray}hline
    & this one & \
    arrayrulecolor{gray}hline
    & & \
    arrayrulecolor{gray}hline
end{tabular}