Is there anything wrong with seekers meditating together if they follow different Masters?
It is not advisable for seekers following one path to meditate with seekers of another path. If you are following one path and the person sitting beside you is following a different path, in spite of your best intentions there will be an inner conflict between your aspiration and his. When you are ready to fly, the person next to you will pull you back. Unconsciously each of you will have the urge to surpass the other. He will try to go beyond you, and you will try to go beyond him. Even if you consciously say, "We are not competing," this does not help. There is an unconscious competition. You feel that your path is better than his, and he feels that his is better than yours.
It is always advisable that the disciples of one spiritual Master meditate only with those on their own path or with those who have not yet chosen a path. It is not that you are being mean; far from it. Only you feel that you live in your house and somebody else lives in his own house.
But when it is a matter of inspiration, if you want to talk with spiritual people who follow other paths, you can. You are trying to reach God, and they are trying to reach God. That means that you and they both possess inspiration. So if you speak with them, you will both get inspiration.