In the role of a support engineer at Buildkite, the author frequently addresses concurrency issues faced by customers, particularly large enterprises with extensive builds. Customers often aim to execute multiple pipelines with a mix of heavy parallelism and enforced sequencing. A typical challenge arises when customers need to lock deployments to environments or end-to-end tests based on current executions. A proposed solution involves using concurrency groups as gates to manage the order of operations while maintaining parallelism. This approach allows customers to run Buildkite pipelines efficiently, ensuring that tests and deployments occur in a specified sequence, with job isolation and multiple build agents, while reducing build time by executing tests in parallel. This method ensures that builds are completed in their order of creation, optimizing the build process without sacrificing the parallel execution of tasks.