Follow these steps to view only your teammates and not everybody when using Quantify gadget.

In order to achieve this, you will need some advanced JQL

1. Create a new Jira filter called "my-team" to define teammates

assignee was in (Person A, Person B) OR creator in (Person A, Person B) 

Depending on your workflow you may keep only assignees

assignee was in (Person A, Person B) 

2. Use this filter with any other JQL statements

Yes, Jira can do that, you can reuse filters and combine them together using filter statement

type=Story and filter=my-team 

It will return tickets with type Story where assignees/creators are part of your team.

3. Bonus part

Nothing prevents from using multiple filters in one JQL. Imagine, that you need to compare different teams based on the same criteria.

filter=bugs and filter=team-alfa 

filter=bugs and filter=team-beta