I assume you're talking about skilled human beings rather than resources. If so, why would QA specialists be considered as anything else other than Developers? Isn't the quality assurance they provide necessary for work to be Done every Sprint and made immediately usable?
There are not titles in Scrum. There is a role called Developers. The people in that role create at least one valuable increment of product each Sprint. That group is made up of cross disciplined individuals that are capable of doing the work necessary to deliver the value needed to satisfy the Product Goal.
In your question you are assuming that there are sub-teams of individuals that are not equal. So how would those individuals choose to organize themselves into teams that are capable of doing the work needed to satisfy the items in the Product Backlog?
Does your organization use a formula to determine how many individuals you need to do Sales based upon the number of individuals you have keeping your Accounts Receivable in order?