Filter by Item Group

Hello,

At Doctype “Item” exist “Item Group” link field.

At “Quotation” I placed a “Select” custom field named “Item Group” including only a couple of item groups. What I want is that the user can only select items (obviously at items table) that belong to the item group selected.

I tried addapting codes like these:

But just can’t make it work.

Also… I found that it’s not possible to unset as “Reading Only” the field “item group” at “Quotation Item” doctype. (I’m using Frappe Cloud).

Any thought would be really helpful!