Toggling multiCapabilites config based on cucumber tag

I was wondering if any one had found a way to toggle between different multiCapabilities configurations coming from a cucumber.conf.js file. Currently I have this one config that will run parallel chrome drivers to run tests.

multiCapabilities: [{
    'browserName': 'chrome',
    'platform': 'ANY',
    shardTestFiles: true,
    maxInstances: 2
}],

But what if I also wanted to add a multiCapabilities option for multi browser testing

multiCapabilities: [{
    'browserName': 'chrome'
},{
    'browserName': 'firefox'
}]

I would rather not want to have to comment out or change code, but rather store a number of multiCapabilities configurations that I can toggle either using something like a flag, tag, or grunt option. Has anyone had any luck with something like this? Thanks!