Ability overriding resource_group globally

Description

We using parallel.matrix, plan, apply and destroy jobs cannot run parallely since the default resource_group: <env>/$CI_COMMIT_REF_NAME is present.

Since I'm using parallel.matrix to apply multiple services independently with the ability to apply only part of the services (in case only some changed), I would like to be able to override globally resource_group (to affect all concerned jobs).

Implementation ideas

Add a new input with its associated environment variable defining the resource_group name (for instance TF_RESOURCE_GROUP and tf-resource-group).

By default it would stay <env>/$CI_COMMIT_REF_NAME.

It should work without issue with the environment variable, however I'm not sure that providing such input resource-group: <env>/$CI_COMMIT_REF_NAME will work 🤔.

I don't have a specific point of view between one input for all environments (we can use $ENV_TYPE to have a different resource_group per job) and one input per environment.

Open to provide the implementation if we agree on this feature.