Webform Issues - updating a One To Many relationship

[DWGray]

Evening Everyone,

I am new to the CiviCRM game and with developers currently refining our new website we are getting close to launch. I have a question about webforms and getting people to update information though. We are using Drupal 7 and Civi 4.4.6 .... I think .... certainly not the current 4.4.LTS albeit still in development "mode".

We are using a modified multi-organisational structure to manage a members database in Civi. We are a national organisation, with local independent organisations and their admin team update their organisations records. One set of fields that they will want to update is the establishments they serve; some have a single (or no) establishment, others have 5 or 6. I have created a Drupal webform to essentially be an "Update Your Details" page and enabled CiviCRM processing with three contacts:

• Individual - Ensuring they are an existing contact with permissions to update their organisations details.
• Organisation - (Member Organisation) With the relevant details we would like them to update
• Organisation - (Establishment) With some details of the establishments they operate within

Additional Information: Each Establishment historically (and probably will only ever) will have one Member Organisation operating there. A Member Organisation however, can have multiple Establishments.
Additional Information: The Individual is independent to the national organisation, therefore we would prefer not to give them direct access to CiviCRM back-end directly, but through webforms.

I am trying to find a method of working, which will allow the Individual to update existing Establishments or create a new establishment and create a relationship to it.
My instincts and the steep learning curve I have endured with being new to Civi suggests that to create a new record and relationship will probably need a separate webform; however that using an auto-complete form which would then populate remaining fields from the Civi record would be viable for updating?

[Coleman Watts]

Are you wanting to have the individual login to your site with a password, or are you wanting to email them a hashed link to grant temporary access to the webform?

[DWGray]

The individual will have a standard username/password log-in as there are other parts of the website which are member restricted.

[Coleman Watts]

Does each individual always represent just one Member Org? Would you ever need a person to log in and manage more than one org? Be careful before you jump to say "no" or you'll get a phone call next week from someone who needs to do just that!

[DWGray]

At the moment the answer is no.

however

I know of one individual who is a member of two organisations.... so the answer can potentially be yes.