```csharp
using Qdrant.Client;

var client = new QdrantClient("localhost", 6334);

await client.CreatePayloadIndexAsync(
	collectionName: "{collection_name}",
	fieldName: "group_id",
	schemaType: PayloadSchemaType.Keyword,
	indexParams: new PayloadIndexParams
	{
		KeywordIndexParams = new KeywordIndexParams
		{
			IsTenant = true
		}
	}
);
```