Declaring same module twice: duplicate ressources - terraform

Question

I am working on a 100% terraform project and I am trying to use the output value from one module into another module. Based on different StackOverflow posts, the most popular way to import the output from module a to module b is to reference the module a inside module b such as:
modules/b/main.tf
module "a" {
source = "./modules/a"
}
After that, you can access output variables from module a inside module b.
My project structure
├── main.tf # declaring all my modules here
├── modules
│ ├── accounts
│ │ ├── main.tf
│ │ └── variables.tf
│ └── organizations
│ ├── main.tf
│ ├── outputs.tf # the var. that I wanna use in accounts
│ └── variables.tf
├── providers.tf
├── variables.tf
└── versions.tf
So my issue is I am declaring all my modules in my main.tf
main.tf
module "organizations" {
source = "./modules/organizations"
}
module "accounts" {
source = "./modules/accounts"
}
However, I need to use one output of module/organizations into module/accounts. And the only way I found to do that is to have (another) organizations module in my modules/accounts/main.tf
modules/accounts/main.tf
module "organizations" {
source = "../organizations"
}
resource "aws_organizations_account" "this" {
name = "uuuu"
email = "udduu#gmail.com"
parent_id = module.organizations.sandbox_organizational_unit_id #HERE
}
But since I already have an organizations module in my main.tf, it's creating/deleting resources in my organization module twice.
organisations/main.tf
data "aws_organizations_organization" "root" {}
locals {
root_id = data.aws_organizations_organization.root.roots[0].id
}
resource "aws_organizations_organizational_unit" "sandboxs" {
name = var.aws_sandboxs_unit_name
parent_id = local.root_id
}
organisations/outputs.tf
output "sandbox_organizational_unit_id" {
value = aws_organizations_organizational_unit.sandboxs.id
description = "ID of the Sandboxs OU"
sensitive = false
}

Answer 1

Neither of your modules should explicitely refer to the other one. Instead, they should declare what kind of variable they expect as input (via a variable key), and what output they provide in return (via the output key)
Then in your main.tf, you can plug everything together:
module "organizations" {
source = "./modules/organizations"
some_variable = module.accounts.some_output
}
module "accounts" {
source = "./modules/accounts"
}
in "organizations", a some_variable must be declared as input: variable some_variable {}
in accounts , a some_output must be declared as output: output some_output { value = ... }