diff --git a/android/proto.go b/android/proto.go
index f466261..c3759f8 100644
--- a/android/proto.go
+++ b/android/proto.go
@@ -16,6 +16,7 @@
 
 import (
 	"android/soong/bazel"
+	"regexp"
 	"strings"
 
 	"github.com/google/blueprint"
@@ -26,6 +27,14 @@
 	canonicalPathFromRootDefault = true
 )
 
+var (
+	// ignoring case, checks for proto or protos as an independent word in the name, whether at the
+	// beginning, end, or middle. e.g. "proto.foo", "bar-protos", "baz_proto_srcs" would all match
+	filegroupLikelyProtoPattern = regexp.MustCompile("(?i)(^|[^a-z])proto(s)?([^a-z]|$)")
+
+	ProtoSrcLabelPartition = bazel.LabelPartition{Extensions: []string{".proto"}, LabelMapper: isProtoFilegroup}
+)
+
 // TODO(ccross): protos are often used to communicate between multiple modules.  If the only
 // way to convert a proto to source is to reference it as a source file, and external modules cannot
 // reference source files in other modules, then every module that owns a proto file will need to
@@ -165,12 +174,11 @@
 
 // Bp2buildProtoProperties converts proto properties, creating a proto_library and returning the
 // information necessary for language-specific handling.
-func Bp2buildProtoProperties(ctx Bp2buildMutatorContext, module Module, srcs bazel.LabelListAttribute) (Bp2buildProtoInfo, bool) {
+func Bp2buildProtoProperties(ctx Bp2buildMutatorContext, m *ModuleBase, srcs bazel.LabelListAttribute) (Bp2buildProtoInfo, bool) {
 	var info Bp2buildProtoInfo
 	if srcs.IsEmpty() {
 		return info, false
 	}
-	m := module.base()
 
 	info.Name = m.Name() + "_proto"
 	attrs := protoAttrs{
@@ -205,3 +213,13 @@
 
 	return info, true
 }
+
+func isProtoFilegroup(ctx bazel.OtherModuleContext, label bazel.Label) (string, bool) {
+	m, exists := ctx.ModuleFromName(label.OriginalModuleName)
+	labelStr := label.Label
+	if !exists || !IsFilegroup(ctx, m) {
+		return labelStr, false
+	}
+	likelyProtos := filegroupLikelyProtoPattern.MatchString(label.OriginalModuleName)
+	return labelStr, likelyProtos
+}