Is it possible to loop through EC2 resources created with a count variable, while in the same module?

Question

I have an EC2 module, which determines the number of instances via a count variable, like so

resource "aws_instance" "this" {
  count = var.instance_count

I would like to subsequently create EBS volumes in the same module, and attach them to each of the instances created. The problem I encountered with this though, is that I need a way to pass the id of each volume to all of the volume_attachment resource, in order to attach each EBS volume to each EC2 instance, so I'd have to have a way to loop through each ec2 id, to then attach all volumes to it.

Which leads to my question: Is there a way to loop through each EC2 instance id, and attach all the EBS volumes to it?

resource "aws_volume_attachment" "this" {
  for_each    = toset(var.ebs_volume_attachments)
  device_name = each.name
  volume_id   = aws_ebs_volume.this.id
  instance_id = module.ec2.id
}

resource "aws_ebs_volume" "this" {
  for_each          = toset(var.ebs_volume_attachments)
  availability_zone = each.availability_zone
  size              = each.size
  encrypted         = each.encrypted
  snapshot_id       = each.snapshot_id
  type              = each.type
  kms_key_id        = each.kms_key_id

  tags = local.tags
} 

Answer 1

What would the value of var.ebs_volume_attachments be?

Wouldn't this work?

resource "aws_volume_attachment" "this" {
  count       = var.instance_count
  device_name = "/dev/sdh"
  volume_id   = aws_ebs_volume.this[count.index].id
  instance_id = aws_instance.this[count.index].id
}

resource "aws_ebs_volume" "this" {
  count             = var.instance_count
  ...
}