All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
We ask Allah to help you and make it easy for you to memorize His Book and act according to it.
It was not clear what was meant by your terms. But if they were symbols that help the memorizer to recognize the similar verses, and remember and memorize their order, then there is nothing wrong with that and there is no religious prohibition for that.
Indeed, many of the reciters of the Quran used to familiarize their students with rules that help them remember and memorize similarities (similar verses). For example, for the verses that start with (أفلم يسيروا), they say: “Ghufira lil-Hajj Muhammad Yusuf”, which means this is located in Surahs Ghafir, Al-Hajj, Muhammad, and Yusuf. In contrast, the verses which start with (أولم يسيروا) are found in other Surahs.
Allah knows best.