How do I turn off Percy snapshots for branches and most ember-try scenarios?

I am using Percy in the tests for an Ember Addon, but the Percy snapshots run 12 times for every pushed commit. I only want them to run for Pull Requests and the main version of my addon.

Here is why they run 12 times right now: - Once for every ember try scenario (6 times) - This is repeated for both PRs and branches pushed to GitHub

I am using Travis CI. How do I cut down the number of times that Percy snapshots run?