Hi @trekco,
Right now this is most likely the best solution: How to programmatically abort instead of fail a build?
Alternatively you can now abort the build using the Bitrise API (Beta): http://devcenter.bitrise.io/api/v0.1/#post-appsapp-slugbuildsbuild-slugabort (related discussion topic: Bitrise.io API v0.1 (Work In Progress))