You'll need to use two grid questions, the first non-required numeric with one column and the second checkbox with three columns. You can combine the two of them with the code here:
https://legacy.sawtoothsoftware.com/forum/28890/add-text-boxes-to-grid
Then give the first grid question this custom JavaScript verification:
var secondGrid = $('#[% QuestionName() %]_div').nextAll('.grid').get(0).id.replace(/_div$/, '');
var secondGridColumns = $('input[name="hid_col_list_' + secondGrid + '"]').val().split(',');
$('input[name="hid_row_list_[% QuestionName() %]"]').val().split(',').forEach(function(row){
if (!SSI_GetValue('[% QuestionName() %]_r' + row + '_c1')) {
secondGridColumns.forEach(function(column){
if (SSI_GetValue(secondGrid + '_r' + row + '_c' + column)) {
strErrorMessage = 'your error message...';
}
});
}
});