I have a line of matrix arrays such as the next figure
Below the code of that matrix.
\begin{figure}
\[
P=\left(\left\{\begin{array}{l}
p^{(1)}(x_1,x_2,\cdots,x_{r_1}) \\
\vdots\\
p^{(m_1)}(x_1,x_2,\cdots,x_{r_1})
\end{array}
\right.%%%%%%%%%%%%%
\left\{\begin{array}{l}
p^{(m_1+1)}(x_1,x_2,\cdots,x_{r_1}, x_{r_1+1},x_{r_1+2},\cdots,x_{r_2}) \\
\vdots\\
p^{(m_1+m_2)}(x_1,x_2,\cdots,x_{r_1}, x_{r_1+1},x_{r_1+2},\cdots,x_{r_2})
\end{array}
\right.%%%%%%%%%%%%
\right).
\]
\end{figure}
Could you help me to break each system such that the new figure approximately will be in this way (with the braces):