You can use either another peg list or a memory palace to keep track of other peg lists or memory palaces.
Example: I have a group of 10 memory palaces that I keep in order with a number shape system. The number shape image is placed before the first location of the memory palace.
Reversing the idea, where you keep track of peg lists with a memory palace, should work too.
Example: if you have two peg lists, and one is a number shape system starting with a candle (for 1), and the other is a number rhyme system starting with gun (for 1), then the first location of your index memory palace could contain an image of a candle and the second location could contain an image of a gun.
If you’re forgetting what is in the peg lists after time, try reviewing the lists more frequently.
There are some related threads here: