I am writing data as matrices into excel file using Matlab. My matrices' dimension varies and I don't know the matrices' dimension in advance. Let's say I have matrix A, B, and C of various dimensions. What I want to do is to write matrix A into excel first and write matrix B after A with 1 column of gap between them. I don't know if there is a way Matlab could find the last column index in excel and create a gap between these two matrices. 

My code is something like this now:

```
xlswrite('My file.xls',A,'My Sheet','B2');

%%
Here is what I don't know to fill in to find the starting range index for my next matrix. 
%%

xlswrite('My file.xls',B,'My Sheet','newindex');

```