You could do something like this:
(1) Identify the rows that match.
idx1 = find(ismember(tableName.variableName,[1 2 3])); % Apply your logic here.
(2) Get the neighboring rows
idx2 = unique([idx1; idx1-1; idx1+1])
(3) That step might get you row number zero, and a row beyond the size of the table, so trim those
idx2 = max(1,idx2);
idx2 = min(size(tableName,1),idx2);
idx2 = unique(idx2); % Might have double-counted the first and last row, so get rid of those. (Could do this better)
