visualizing 2D-graphs of n-dim. array via surf()

Hello,

I want to show 2dim. surface plots for different combinations of 2 parameters of a 3- or higher-dimensional array in matlab. The data for the non-shown dimensions are integrated (i.e. summed in the remaining dimensions). I am using surf(), and for parameter combinations other than (1,2) (eg. (1,3), (2,3) ...) I have to rearrange the data matrices in order to make it work.

I am looking for an alternative command (or shorter code) which does this work.

Here's the code:

a=zeros(3,3,2);  
a(:,:,1) = [1 2 3 ;4 5 6; 7 8 9; 10 11 12];       % data matrix   
a(:,:,2) = -[1 2 3 ;4 5 6; 7 8 9; 10 11 12]*2;    % data matrix  
ai=[[1 2 3 4]' [5 6 7 0]' [8 9 0 0]'];      % parameter vector  

mat12 = sum(a,3);  
surf(ai(1:3,2),ai(1:4,1),mat12)  

aux13 = sum(a,2);                         
for i = 1:2; mat13(:,i) = aux13(:,:,i);     
surf(ai(1:2,3),ai(1:4,1),mat13)  

aux23 = sum(a,1);  
for i = 1:2; mat23(i,:) = aux23(:,:,i);     
surf(ai(1:3,2),ai(1:2,3),mat23)

In other words, I am looking for a way to use surf for matrices mat13 and 23 without the aux13, aux23 variables and the for loop.

Thank you very much for any hints!