Yes, but only for stretching/conditioning. For apparatus work and technique, you would have to train at an rg club.
I you want oversplits, there’s really only one way to get them: to stretch in oversplits. Start small; use a book or a pillow under your front leg. Stretch for a minimum of 2 minutes each leg. Then, as you get better, use a pile of books, or a chair to increase the stretch. Once you can sit on one chair, I suggest you move to two chairs to stretch the back leg as well. For rings/scorpions, you will need to stretch your back and shoulders. For back, (assuming you’ve already warmed up!) practice chest stands and try and get your feet to reach the floor. Once you’ve done that successfully, try to straighten you legs as much as possible. Other stretches include: bridges, on elbows and on hands, arching in splits and grabbing your back leg and straightening it. (Like the one in the second image in the first picture/ 2nd picture if you have your oversplits) Sorry, im not sure what box splits or Y stands are, I don’t use that terminology :P Hope this helps!!
The longer, the better! Start out by sitting for 30 sec. Then increase to 1 min. Then as you get more used to it, increase to longer, such as 2-5 minutes at a time! Just remember to stretch both legs!
Have any questions about rhythmic gymnastics, stretching, or anything else? FEEL FREE TO ASK! (: