"break" only acts on the immediately enclosing loop. It already does what you want.
For example,
>> for K = 1 : 5; X = 0; while true; X = X + 1; disp([K,X]); if X>K; break; end; end; end
1 1
1 2
2 1
2 2
2 3
3 1
3 2
3 3
3 4
4 1
4 2
4 3
4 4
4 5
5 1
5 2
5 3
5 4
5 5
5 6
You can see from the output that the break is working but that the containing "for" continues.
