In Vastu Shastra, Acharya Indu Prakash talks about the relation of Mars with other planets. For Mars; Sun, Moon and Guru are considered friends, Venus and Saturn are even, while Mercury is the enemy. According to this, you should keep things related to Mars close to things related to Sun, Moon and Guru as this will benefit you and keep the vastu dosh away.
Venus and Saturn-related things can also be kept with that of Mars. Even if you do not get much benefit from this, then there will be no loss of any kind as well. But keep in mind you should avoid keeping the Mercury-related things with Mars. So by knowing the relation of one planet to another, you can keep the Vastu of your house in order.
