如何使用poi在Excel中添加多选下拉列表

I have an list of Strings (A,B,C,D,E) and i have added this list to cell using range and data validity in libre office. but it only selects one value at a time. I want something like if i select first D and then C output should be like D,C multi-select. I have already studied all the questions on stack overflow but i haven't found anything. Thanks, in advance.I have an list of Strings (A,B,C,D,E) and i hav