MATLAB: (continued)On the combination of N-dim vector.

vector; constraint

Yesterday I asked how to write code to visit every combination of N-dim vector(with entry 0,1 or 2), and it is very helpful by just trying below:
[C{1:N}]=ndgrid(0:2);
M=reshape(vertcat(C{:}),[],N);
Then for i=1:3^N, trying M(i,:) is the answer. However, if I want to add constraint on those 3^N vectors, how to adjust the code?
For example I want all combinations that less than or equal to another vector V(every entry is less than or equal to V's entry). For another one, I want to try those combinations in a order, by least sum of all entries to most.
Thank you for your help!
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