Hi Zoho Community

I need some orientation  creating relations between forms in my app. I will explain you what I have and what I want to do.

I have a Catalogue, where my products are.

I have Purchase Request form (PR), trough this form all departments in the company request the products they need to the purchase department.

this form(PR)has a subform (PR Detail), that has a Description field, which is a lookup field to the Catalogue. It also has quantity field and Status field (dropdown with 3 choises: pending, approved, not approved)

I Also have a Purchase order form (PO), through this form the purchase department generate all orders for external providers and dealers.

In PO there is subform too (PO Detail), with description lookup field to catalogue, also a quantity field, cost and Status

I would like to see in the PO Detail lookup field only the products that where previously requested through the PR form  and also related with the quantity.

And when a Purchase order with this products is successfully generated update their status to approved.

Any help will be very appreciated