If you need to hire fast, there are ways to get the group to be effective quickly. If you normally work on long projects, it could take a long time before everyone gets a chance to interact, debate, reach conclusions and pull together to deliver. So, why not get everyone together and run a mini-project over a few days - a sharp, intense, end-to-end experience which really forces people together to debate, conclude and deliver. That can really accelerate the group's transition from forming/storming into norming/performing.