diff --git a/kv/kv.go b/kv/kv.go
index 12bf56c8..ad3878c7 100644
--- a/kv/kv.go
+++ b/kv/kv.go
@@ -25,6 +25,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/pingcap/kvproto/pkg/kvrpcpb"
 	tikverr "github.com/tikv/client-go/v2/error"
 	"github.com/tikv/client-go/v2/util"
 )
@@ -66,7 +67,12 @@ type LockCtx struct {
 	LockExpired           *uint32
 	Stats                 *util.LockKeysDetails
 	ResourceGroupTag      []byte
-	OnDeadlock            func(*tikverr.ErrDeadlock)
+	// ResourceGroupTagger is a special tagger used only for PessimisticLockRequest.
+	// We did not use tikvrpc.ResourceGroupTagger here because the kv package is a
+	// more basic component, and we cannot rely on tikvrpc.Request here, so we treat
+	// LockCtx specially.
+	ResourceGroupTagger func(*kvrpcpb.PessimisticLockRequest) []byte
+	OnDeadlock          func(*tikverr.ErrDeadlock)
 }
 
 // LockWaitTime returns lockWaitTimeInMs
diff --git a/txnkv/transaction/pessimistic.go b/txnkv/transaction/pessimistic.go
index 9064aaf3..683a1a45 100644
--- a/txnkv/transaction/pessimistic.go
+++ b/txnkv/transaction/pessimistic.go
@@ -119,6 +119,9 @@ func (action actionPessimisticLock) handleSingleBatch(c *twoPhaseCommitter, bo *
 		MinCommitTs:  c.forUpdateTS + 1,
 	}, kvrpcpb.Context{Priority: c.priority, SyncLog: c.syncLog, ResourceGroupTag: action.LockCtx.ResourceGroupTag,
 		MaxExecutionDurationMs: uint64(client.MaxWriteExecutionTime.Milliseconds())})
+	if action.LockCtx.ResourceGroupTag == nil && action.LockCtx.ResourceGroupTagger != nil {
+		req.ResourceGroupTag = action.LockCtx.ResourceGroupTagger(req.Req.(*kvrpcpb.PessimisticLockRequest))
+	}
 	lockWaitStartTime := action.WaitStartTime
 	for {
 		// if lockWaitTime set, refine the request `WaitTimeout` field based on timeout limit