How can I merge two events in logstash?

Question

I'm trying to parse a log file into elasticsearch through logstash.

I want to send the following log as single event(i.e. as a single document) into elasticsearch.

Here is my log file looks like:

######################################################
ETL Wrapper Initializing - 09/27/2018 06:33:57
######################################################
------------------------------------------------------
Wrapper Information - 09/27/2018 06:33:57
------------------------------------------------------

------------------------------------------------------
Reading Component Log Port Files - 09/27/2018 06:34:53
------------------------------------------------------
-- >     -- > Found 3 files and only merge non-zero byte files
------------------------------------------------------
Renaming Reject Files - 09/27/2018 06:34:56
------------------------------------------------------
######################################################
Sending Notifications - 09/27/2018 06:34:56
######################################################
------------------------------------------------------
Setting Exit Status - 09/27/2018 06:34:56
------------------------------------------------------
######################################################
ETL Wrapper Finalizing - 09/27/2018 06:34:56
######################################################
------------------------------------------------------

Here is my logstash configuration:

input {
file {
path => "D:/logs/file.log"
start_position => "beginning"
}
}
filter{
grok {
match => {"message" => "ETL Wrapper Initializing - %{DATESTAMP:JobStartTime}"}
match => {"message" => "ETL Wrapper Finalizing - %{DATESTAMP:JobEndTime}"}
}
if "_grokparsefailure" in [tags]{
drop{}
}
if [message] =~ /^$/ {
        drop { }
}
mutate{
    remove_field => ["@version","host","message" ]
    }
}
output {
elasticsearch {
    hosts => "http://localhost:9200/"
    index => "success_index"
    }
stdout { codec => rubydebug }
}

Output of above configuration:

{
    "JobStartTime" => "09/27/2018 09:33:41",
      "@timestamp" => 2018-12-05T10:55:44.698Z,
            "path" => "D:/logs/file.log"
}
{
    "JobEndTime" => "09/27/2018 09:34:16",
    "@timestamp" => 2018-12-05T10:55:44.784Z,
          "path" => "D:/logs/file.log"
}

My expected output:

{
    "JobStartTime" => "09/27/2018 09:33:41",
      "@timestamp" => 2018-12-05T10:55:44.698Z,
            "path" => "D:/logs/file.log"
    "JobEndTime" => "09/27/2018 09:34:16"
}

How can I merge "JobStartTime" and "JobEndTime" into single document?

Any help is appreciable.. Thanks in advance!