Hello I am late to this but in general it is not a good idea to house males together. They will get along most of the year but during mating season, they have been known to kill each other.
Also if you put more than one male with a female they might kill her during breeding season.
I have had males in the same cage but I had a divider and during breeding season they fight through the bars.
For best results if you want singing, I suggest you have two males in seperate cages or with a divider and a female in another cage where they can see her or at least hear her. Then the males sing like crazy trying to compete for her attention.