Bunch is tool for grouping, managing and running Lettuce scenarios. It offers explicit separation of test fixtures from test scenarios by dividing it into setup, teardown and test scripts. Bunch encourages writing clean, self-sufficient and multi-environment tests. It also provides more flexibility for test parameterization - test scenarios are treated as templates, which get parameterized upon execution.
You can find full documentation for Bunch at Grid Dynamics web site here or inside docs directory.