Query for SSRS Column Group

Hi,

I have a question regarding the my matrix grouping

My dataset is small containing the names of the teachers who worked for a particular department in a particular month

Each teacher teaches only one subject and only 1 month in a year.

I want something like this 

1:- I added a row group on department 

2:- Column group on year and month 

Issue is in that case I only get one teacher against Maths  for Oct 2018

If I add child row group on teacher name then it spoils the report 

Here is the SQL of dataset

declare @temp table 
(
SubjectName varchar(100),
TeacherName varchar(100),
Month_Name  Varchar(100),
Year_Name   varchar(100)
)


insert into @temp values ('Physics','John','Sep','2018')
insert into @temp values ('Physics','Paul','Dec','2018')
insert into @temp values ('Physics','Sam','Oct','2018')
insert into @temp values ('Maths','Roxi','Oct','2018')
insert into @temp values ('Maths','Paula','Oct','2018')
insert into @temp values ('Physics','Lok','Jan','2019')
insert into @temp values ('English','Kelly','Feb','2019')
select * from @temp

Expected SSRS Report

Thanks in advance