Conveying relationship between form input fields

Context
I'm working on an audience selection workflow where a user can specify certain attributes to select their audience. For example, the user may want to create an audience of entirely male demographic or say, an audience of people who use StackExchange or maybe even an audience with males who use StackExchange, are aged b/w 25-35, live in Vancouver and speak 3 languages.

The problem
The relationship between the different input fields follow specific boolean logic. For example, if the user checks both Male and Female, the result would be a cohort of people who are either Male OR Female. However, if the user selects Male, Female, Facebook, the result would be a cohort of people who are Male OR Female AND use Facebook (NOT male OR female OR facebook users) by default. However, the user, for some cases will be able to change this logic (and turn it into male OR female OR facebook users). How do I convey this boolean relation to the user in the form? This could be confusing especially because not all boolean logic/relation can be changed.