Pokedex Entry Number for alternate forms

I dont think this is duplicated but if it is I do apologise.

I am a tcg collector and i am building a full pokedex binder. To make sure i am doing it correctly i was putting together a page that puts all pokemon in pokedex order that i can print and cutout and put in the slots.

There comes a problem with pokemon that have mega evolutions for example. I know this is a very niche feature but after putting them in order, i found that mega charizard X / Y for example come at the end (after the main 1025) although they actually are number 6 in the pokedex along with base charizard, thus should be next to each other. However, pokemon that have alternate regional forms, they have their own separate pokedex number and entry and are therefore within the current 1025. I guess what i am asking is for a pokedex entry number or order number to be included in the results so that they can be organised accordingly.

I know that there is an order number but it doesn't seem to follow this idea from what i can gather and i am unsure what it is used for.

Start by checking how alternate forms and the existing order field are represented in the PokeAPI results. Clarify how a Pokédex entry or ordering value should group Mega Evolutions with their base Pokémon while preserving separate regional-form entries; done means the API exposes a consistent value that produces the requested ordering.