So far there is no circular sent to make people play the National Anthem during the wedding. But this was the idea of the groom.
BS Shrinivas Raje Urs got married to M Saritha Urs at Chikkamagalur. Shrinivas works as a software engineer in the South Africa. As soon as the Mangalageethe (last part of the wedding) was over, Shrinivas asked those managing the sound system to play the recorded National Anthem. As the Anthem started, all the people gathered for the wedding stood up.
This act by the groom was appreciated by many who attended the wedding. But just for information, there is no such rule to play the National Anthem after the wedding.