Assuming that you have a multiple relation from Quotes to Groups, and then another multiple relation from Groups to Items, then you could do the following:
- In your Groups table, create a Joined List column that targets the Item Name through the multiple relation to Items
- In your Quotes table, create a Joined List column that targets the above column through the multiple relation to Groups
- This should give you a list of all Items associated with each Quote.
- To transform that list into something that could be used as the source of an Inline List, you can use the Miracle Method