\begin{tikzpicture}[
    node/.style={inner sep=0pt},
    simplebox/.style n args={3}{
        rectangle, rounded corners, thick,
        draw=black, fill=#1,
        minimum width=#2,
        minimum height=#3,
        inner sep=10pt, inner ysep=10pt
    },
    simpleboxtitle/.style = {
        rectangle, rounded corners=0,
        minimum width=1em,
        fill=brown!10, text=black, draw, thick,
        font=\bfseries,
        inner sep=3pt
    },
    header/.style = {%
        inner ysep = +1.0em,
        append after command = {
            \pgfextra{\let\TikZlastnode\tikzlastnode}
            node[simpleboxtitle] (header-\TikZlastnode) at (\TikZlastnode.north) {#1}
        }
    },
    coloredHeader/.style n args={2}{
        inner ysep = +1.0em,
        append after command = {
            \pgfextra{\let\TikZlastnode\tikzlastnode}
            node[simpleboxtitle,fill=#2] (header-\TikZlastnode) at (\TikZlastnode.north) {#1}
        }
    }
]

    \node[simpleboxtitle] (orgs01) [] {Org. $\pmb{\alpha}$};
    \node[simpleboxtitle] (orgs02) [below = 0.3em of orgs01] {Org. $\pmb{\omega}$};
    \node[fit = (orgs01) (orgs02)] (orgs0) {};
    \node[simpleboxtitle] (orgs1) [above right= -0.8em and 4em of orgs0] {Org. $\pmb{\omega}$};
    \node[simpleboxtitle] (orgs2) [below = 3.5em of orgs1] {Org. $\pmb{\gamma}$};
    \begin{scope}[on background layer]
        \node[yshift=2pt, fit = (orgs01) (orgs02), simplebox={gray}{1em}{2em}, coloredHeader={MISP 1}{blue!10}] (m1) {};
        \node[yshift=2pt, fit = (orgs1), simplebox={gray}{1em}{2em}, coloredHeader={MISP 2}{blue!10}] (m2) {};
        \node[yshift=2pt, fit = (orgs2), simplebox={gray}{1em}{2em},  coloredHeader={MISP 3}{blue!10}] (m3) {};
    \end{scope}

    \draw[-, thick] (m1) to[out=20, in=180] (m2);
    \draw[-, thick] (m1) to[out=-20, in=180] (m3);
\end{tikzpicture}