Can you keep 2 ganders and a goose together?

No! and not recommended! Just like you can't keep two roosters and a hen. The ganders will fight at some point for dominance and it will never end.

The only exception is if they were all raised as goslings together. If they were all babies together they might grow up fine and not fight but if they are adults from diferent groups then big NO.

Get more goose if you are going to keep both ganders, maybe they will pair up and not fight. If you have them together now and they're getting along keep an eye on them and maybe there will be no problem but at first sign of fight which can get bad you need to separate.

Sometimes if they are in a big open area, free ranging or in a large barnyard environment they will get along great! Many people have 3-5-10 ganders in with 10-20 geese and they all get along.