Creating bi-directional relationship through lookup

Creating bi-directional relationship through lookup

Hi,

We are building our inventory module. We currently have a challenge. Will be helpful if some one suggest a fix.

Overview of the process.

1. An order for an item gets booked. Here order booking is form, and list of items booked are through a     form embedded as a subform.
2. List of items to be ordered is a lookup field from inventory master form.
3. When list of items to be ordered is booked by customer, each part ordered quantity is to be updated        in the inventory master forms field Order Quantity.

Example of the form, subform and field


Regards,
Srini.