Using two custom filters prevents one of them to be used

I created two filters; logstash-filter-one and logstash-filter-two. When I tested logstash-filter-one, it worked just fine and created the fields I wanted it to. However, when I used logstash-filter-two alongside logstash-filter-one, only the fields created by logstash-filter-two showed up..

the following is my config file

input { ... }

filter {

one {
      process => "%{message}" #must create field called process_one
}

two {
      process => "%{message}" #must create field called process_two
}

}

output { ... }

Why aren't both process_one and process_two being created? Help please!!

thanks.

What does the source code of these two plugins look like?