Exclude folders from builds in Brocfile

Is there a way to exclude a folder from a build in a Brocfile (or any other place). The use case is packaging, where I have an app made of sub-apps within pods. eg.

/app/modules/components
/app/modules/app1
/app/modules/app2
/app/modules/app3

I'd like to build them all when environment is set to 'development' or only eg. 'app1' when environment is 'app1'. Any suggestions?

I have tried different combinations of broccoli-file-remover, broccoli-funnel and broccoli-merge-trees to no avail.

var removeFile = require('broccoli-file-remover');

module.exports = removeFile(app.toTree(), {
    paths: ['app/modules/pod1/', 'app/modules/pod2/']
});