Bringing a male into female household

Question
We have a female Great Dane (1 1/2 years old), and a female Rhodesian Ridgeback (2 years old). We are considering adopting a MALE Great Dane (7 years old) from a friend who cannot keep him anymore. The male is extremely gentle and friendly. So are our 2 females. How would you suggest that we introduce them to each other ? Many thanks for our answer

Answer
Introduce slowly, one bitch at a time.  Don't let them play too hard.
 Don't leave them all loose together, who knows what mischeif they may get up to as a pack.  Watch the bitches when they are due in season, they may start fighting over the male.

Ken