Macro To Sum Lines With Same Criteria

[crashing1912]

I need a macro to "subtotal" the data below. Basically, there are invoices that can have different "Types" of costs on them, however, sometimes the information provided by the billing dept. the types can be repeated. For example, invoice 57 for Kansas has P listed twice, as well as T. I need the macro to sum columns Gross, Discount & billed for "P" on to one line.
The criteria would be sum Gross, Discount, & billed when the state, invoice & type are the same.

State	Invoice	Type	Gross	Discount	Billed
Michigan	56	T	500	0	500
Michigan	56	R	100	0	50
Kanas	57	P	100	0	100
Kansas	57	P	300	0	300
Kansas	57	T	100	0	100
Texas	58	R	200	0	200
Texas	58	R	100	0	100
Oklahoma	59	T	200	0	200
Oklahoma	59	T	300	0	300

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The end result should look like this:

State	Invoice	Type	Gross	Discount	Billed
Michigan	56	T	500	0	500
Michigan	56	R	100	0	50
Kansas	57	P	400	0	400
Kansas	57	T	100	0	100
Texas	58	R	300	0	300
Oklahoma	59	T	500	0	500

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