Logstash- transfrom multiple log lines to one line

I have a situation where I am getting logs from forwarder in the below format:

timestamp <uniquerID> entry: ProcessAPI{AddEmployee} :hostname
timestamp <uniquerID> send: UserAPI{ValidateUser} :hostname
timestamp <uniquerID> receive: UserAPI{ValidateUser} :hostname
timestamp <uniquerID> send: AccountAPI{ValidateAccount} :hostname
timestamp <uniquerID> receive: AccountAPI{ValidateAccount} :hostname
timestamp <uniquerID> exit: ProcessAPI{AddEmployee} :hostname

I want to combine these log line to a single line like below format:

timestamp <uniquerID> Exit:ProcessAPI{AddEmployee}:hostname | UserAPI{ValidateUser}:hostname | AccountAPI{ValidateAccount}:hostname 

Is there a way in Logstash to do this.?

Update: Each log line has associated parent service name in the source field as below:

@Source: ProcessAPI{AddEmployee}
@Message : timestamp send: UserAPI{ValidateUser} :hostname

Look at the multiline codec.

Is multline is threadsafe.I am seeing from the Logstash info stating that multiline is not thread safe.

We need a solid solution to concat these either using multiline,merge or aggregate

The current multiline codec documentation says nothing about thread safety.

Is multiline will be achieved for where we have many logs like this coming from different services

I tried Multiline codec , but its combining the whole logs to an array.

The scenario here is that I have same types of logs coming from many services in bulk.

Example :
Service A calling --> Service B

So logs for both service A as well as service B will be shipped to logstash simultaneously.

How would I combine logs of service A as single line and logs for Service B as another single line.