Any standard GSUB feature tag for infant/single-storey variants?

Hi all

As making a Chinese typeface I'd like to give a final solution for the Pinyin-European problem. When typesetting European words the letter a and g are usually double-storey, however when used for Pinyin, a phonetic notation system often used for Chinese elementary education, to prevent children from mimicking the shape of the letters, the a and g are usually single-storey. So aside from stylistic sets, are there any standard GSUB feature tags for such a conversion?