RDSforsqlserver怎样使用事务？

有两个数据库ds_server_a/catalog_a和ds_server_b/catalog_b，代码如下所示，怎样能够保持db和db2使用同一个transaction呢？求赐教！

var dbFactory = new OrmLiteConnectionFactory(
                "Data Source=ds_server_a;Initial Catalog=catalog_a;Integrated Security=True;Connect Timeout=15;Encrypt=False;TrustServerCertificate=False",
                SqlServerDialect.Provider);

            var otherDbFactory = new OrmLiteConnectionFactory(
                "Data Source=ds_server_b;Initial Catalog=catalog_b;Integrated Security=True;Connect Timeout=15;Encrypt=False;TrustServerCertificate=False",
                SqlServerDialect.Provider);
            try
            {
                using (IDbConnection db = dbFactory.OpenDbConnection())
                {
                    using (IDbConnection db2 = otherDbFactory.OpenDbConnection())
                    {
                        using (IDbTransaction tran = db.OpenTransaction())
                        {
                            db.Insert(new BaoLi2136 { Id = 2140, content = "Employee 1" });

                            db2.Insert(new Bl2136
                            {
                                id = 2140,
                                phone = "123123123",
                            });
                            tran.Commit();

                        }
                    }
                }
            }
            catch (Exception ee)
            {
                Console.WriteLine(ee.Message);
            }