Inverse of Partioned Matrix

Question

I have a matrix $A_{(mn)*(mn)}$, which could be partioned into $m*m$ matrices $B_{n*n}$. My goal is to find the inverse of $A$.
Sepcifically, let's say $B_0=\begin{bmatrix} b_1 & 0 & 0 \\ 0 & \ddots & 0\\ 0 & 0 & b_n \end{bmatrix}$, a diagonal matrix. $B_i=B_0+C_i=\begin{bmatrix} b_1+c_i & c_i & c_i \\ c_i & \ddots & c_i\\ c_i & c_i & b_n+c_i \end{bmatrix}$, a symmetric matrix. Then $A=\begin{bmatrix} B_1 & B_0 & B_0 \\ B_0 & \ddots & B_0\\ B_0 & B_0 & B_m \end{bmatrix}$, still a symmetric matrix.
Now I want to find $A^{-1}$.
I am not very familiar with matrix inverse but I feel like inverse of every matrix $B$ is easy to do. So the question is how can I get $A^{-1}$ from $B^{-1}$'s? Thank you!