MATLAB: How create a matrix that matches a condition in comparison with other matrix

loopmatrixmatrix manipulation

The matrix A is given by several repeated values of A(:,1) positions with different A(:,2) values like:
clc;clear all
A=[
1   10
1   9
1   8
1   7
1   6
2   15
2   14
2   13
2   12
2   11
3   18
3   17
3   16
3   15
3   14
4   12
4   11
4   10
4   9
4   8];
scatter(A(:,1),A(:,2),'filled','r')
Represented by the following red dots:
The matrix B, represents 1 [X,Y] combination for each B(:,1) as:
%%

B=[
1   8
2   14
3   11
4   12];
 
hold on
scatter(B(:,1),B(:,2),'filled','b')
How can I eliminate all the values extrictly higher than any B(:,2) for each B(:,1) and keep only same or lower values getting a C matrix like:
%%
C=[
1   8
1   7
1   6
2   14
2   13
2   12
2   11
4   12
4   11
4   10
4   9
4   8];
scatter(C(:,1),C(:,2),'filled','g')
green dots represent the wanted points to keep.

Best Answer

A=[
1   10
1   9
1   8
1   7
1   6
2   15
2   14
2   13
2   12
2   11
3   18
3   17
3   16
3   15
3   14
4   12
4   11
4   10
4   9
4   8];
B=[
1   8
2   14
3   11
4   12];
idx =  cell2mat(arrayfun(@(i){A(:,1)==B(i,1) & A(:,2)<= B(i,2)},1:size(B,1))); 
[rowIdx,~] = find(idx);
C = A(rowIdx,:)
C = 12×2
     1     8
     1     7
     1     6
     2    14
     2    13
     2    12
     2    11
     4    12
     4    11
     4    10

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