Creating argument to filter multiple NID's in a single filter-criteria
The "Contextual filter" solution is only needed if you wish to filter your results dynamicly by passing the necessary filters through the URL. 

If I understand your question correctly you wish to filter your view on 4 specific nid's only (witch will never change)? 

In that case you could modify your views filter setup and split into 4 seperate filters (each filtering on 1 nid). In the dropdown menu (where you have the "add" button to add a new filter) you have a config page where you can rearrange your filters and more importantly you can specify conditionals using filter group's. In your case I would create a second filter group for the 4 nid filters and use the "Or" operator between them.