Counting Unique Values from a Set List Based on Another Cell's Conditions

I need help figuring out a formula that will allow me to count the number of unique occurrences for a list of values that show up within specific categories.

Basically, I have data like this:

	A	B
1	Booking Type	Room Number
2	Office Hours	123
3	Office Hours	125
4	Event	200
5	Class	101
6	Event	200
7	Office Hours	123
8	Office Hours	145
9	Class	145
10	Event	202
11	Class	101

And I have to figure out how many different rooms have been used for, say, Office Hour bookings. But, in addition, there are different types of rooms and I need to break it down further by room category.

For example:

Classrooms	101, 145, 147, 148
Study Rooms	123, 125, 134, 191
Event Spaces	200, 202

So I need data to fill in the following:

	A	B	C	D	E
1	Booking Type	Total Unique Classrooms Used	Total Unique Study Rooms Used	Total Unique Event Spaces Used	Total Unique Spaces Used
2	Office Hours	??	??	??
3	Event	??	??	??
4	Class	??	??	??

Total Unique Spaces Used is fairly straight-forward. I'm getting really stuck on trying to figure out how many different classrooms were used specifically for Office Hours booking, for example.

H2=SUMPRODUCT((MATCH($A$1:$A$11&$B$1:$B$11,$A$1:$A$11&$B$1:$B$11,)=ROW($A$1:$A$11))*($A$1:$A$11=$G2)*(ISNUMBER(FIND($B$1:$B$11,INDEX($E:$E,COLUMN(A1)))))*1) copy to J4