I think there is a confusion - old fashioned at best, dangerous at worst - that the only way of meeting children's different needs within a classroom is to put them into fixed different groups with different work to do.
The vast, vast majority of the time, that isn't the best way to meet children's needs, and in many cases will cap the progress that can be made by children throughout the class.
Think about a 'typical' week of. say, English. On day 1, we might read a text, or might have some type of experience about which we are going to write - no need for groups, mixed ability discussions are by fa the best. Yes, some individual children might have had the text pre-read to them as part of the previous week's plan, or might have previously discussed key vocabulary, or might have key vocabulary in their home language with a translation, or might read the book again with an adult later in the day, or might have it simultaneously signed, but there is no need for groups. Equally there is no need for groups as the class is taught as a whole and tackles a new writing objective linked to the text the following day, or gathers new vocabulary, or re-enacts part of the story. There MIGHT be a need for groups the day that objective is repeated - flexible groups, responding to the previous day's marking. there might be a couple of children who revisit the basic objective, others who hasten on, others who apply it in a different context. Then back together as a mixed class to discuss characters, plot, setting, whatever is going to be the output, and individual work when writing - supported by materials, people, resources, additional input as needed.