SQL Server 2008 :: Roster Rotating Persons Within Each Department For Available Dates

I need to prepare a roster rotating persons within each Department for the available dates

Please refer to the below sample tables and data

CREATE TABLE Roster
(
StartDate Date,
EndDate Date
)
CREATE TABLE Department

[Code] ....

Expected Output

SELECT '01/01/2015' StartDate, '01/05/2015' EndDate, 'A' Department,'P1' Person
UNION
SELECT '01/01/2015' StartDate, '01/05/2015' EndDate, 'B' Department,'P3' Person
UNION
SELECT '01/01/2015' StartDate, '01/05/2015' EndDate, 'C' Department,'P6' Person

[Code] .....