How are children grouped together in public schools for help in their learning disabilities?

Healthy11 has it right...at least theorectically. I wish I could say that is how it always works. Unfortunately in our school system, children are placed based on diagnosis and performance. Those who are the furthest behind are placed in "Life Skills" classes which focus on basic skills such as feeding, dressing etc. There are other classes such as "AU" for autistic children on various ends of the spectrum, but usually reserved for those with moderate to severe disability. There are also resource classes for those that can function effectively socially but need additional help academically. I wish the school TRULY individualized, but they do not always do what ARD's and IEP's were developed to do.

EVERY child is different, and every school is different as far as how they address the needs of children with LDs. Does your child have an IEP? What kind of diagnosis do they have, and what kind of classroom environment are they in? Have you visited it? While, for privacy reasons, the school can't tell you what every other child in the room is dealing with, most states have guidelines for the teacher: student ratios of children with particular types of disabilities being together. Realize, however, that even students who might have the same diagnosed LD can't all be treated the same way, which is the whole reason students are supposed to have IEPs (INDIVIDUALIZED education plans.)
For example, even if you have two children in the same grade with reading disabilities, one may have problems with sound-letter correlation and decoding words, while another may have more difficulty with comprehension. The remediation approach used with one student won't necessarily help the other.

I'd like to invite you to join Greatschools Learning and Attention Difficulties Group at community.greatschools.net/groups/11554 for more information and support.