Jesus promises when we love one another, God will answer our prayers. This is especially true when we come together in love and agreement and harmony with one another.
This is why evil spirits work so hard to create disunity between husbands and wives, between families, between church people and so on. The devil is frightened of what we could achieve if only we could sit down and pray with united hearts!
The results we get in prayer depend on our general obedience to God, especially in the way we love.
Praying together is encouraged by Jesus for a reason. It will get much better results when it is done from loving, united hearts.