To create Namco, Konami, etc. you can either create a filter for MAME or a new display using the MAME romlist. You don't need the master romlist for these.
Here's an example to create a new MAME filter for Namco:
Configure-->Displays-->MAME-->Add Filter-->Enter Filter Name=Namco-->Add Rule
Target=Manufacturer
Comparison=contains
Filter Value=Namco
Here's an example to create a new Namco display:
Configure-->Displays-->Add New Display-->Enter Display Name=Namco
Collection/Rom List=MAME
Global Filter-->Add Rule-->
Target=Manufacturer
Comparison=contains
Filter Value=Namco
If you want your "Fighter Games" to include multiple systems you should create the master romlist. Once it's created you can make a new display for it using a filter like this.
Configure-->Displays-->Add New Display-->Enter Display Name=Fighter Games
Collection/Rom List=All Systems
Global Filter-->Add Rule-->
Target=Category
Comparison=contains
Filter Value=Fight
If the above filters don't give you exactly what you want you can use tagging to get the exact game list you want following these steps.
1. create the master romlist (this will be needed if you want to include games from different systems)
2. using the master romlist, create tags for whatever you want (Namco, Konami, Fight, etc.)
3. using the master romlist, apply the tags to the games you want
4. you can now create filters for the master romlist or create new displays with filters for your tagged games
Example for a new display with a filter for Fighter Games:
Configure-->Displays-->Add New Display-->Enter Display Name=Fighter Games
Collection/Rom List=All Systems
Global Filter-->Add Rule-->
Target=Tags
Comparison=contains
Filter Value=Fight