How to get values out of IGrouping?

I have applied IGrouping<> over a list - here's what it looks like: ``` IEnumerable<IGrouping<TierRequest,PingtreeNode>> Tiers { get { return ActiveNodes.GroupBy(x => new TierRequest(x.TierID, x.TierTimeout, x.TierMaxRequests)); } } ``` Later in my code I iterate over Tiers. Its simple to get the key data using the Key element, but how do I get the `IEnumerable<PingtreeNode>` that forms the value part? Thanks in advance