Multi-Step Filtering Buttons with RegExp

I'm trying to make a filter button I can use anywhere to show specific types of content and hide everything else:

At the moment, I'm leveraging saved filters to do this. Each of the buttons in the menu above looks something like this:

Select NOPATTERN SHOWHIDDEN
Select "Images Only" FILTER HIDEUNSEL SHOWHIDDEN DESELECTNOMATCH
Select NONE

This clears any existing filters and then filters the display based on the saved filter.

What I'd like to to is add some buttons that further filter the contents — .i.e.,

(1)
clear existing filters:
Select NOPATTERN SHOWHIDDEN

(2)
look at only image files:
Select "Images Only" FILTER HIDEUNSEL SHOWHIDDEN DESELECTNOMATCH

(3)
further filter the results to show only screenshots:
Select ^[Ss]creenshot_.+$ REGEXP HIDEUNSEL SHOWHIDDEN DESELECTNOMATCH

(4)
further filter the results to show only screenshots from a given source:
Select ^.+_Google\.{file|ext} REGEXP HIDEUNSEL SHOWHIDDEN DESELECTNOMATCH

(5)
do away with the selection so I'm left with a list of files
Select NONE

... but my approach isn't doing the trick. I'm just selecting a new set of files with each step in (2), (3), and (4) instead of narrowing down the selection to what I'm looking for.

I could make a single regex for this and save it as a Filter — but I'd prefer to leverage the Images Only filter and then add additional filtering in the individual buttons. This allows me to keep Images Only "pure" and update it with new image types I may discover or filter for in the future without filling up my Saved Filters list with hyperspecific filters I'm only using in buttons that will all have to be updated individually if I start using a new image file type.

There's probably a dead-simple syntactical solution I'm missing, likely to do with what I'm leaving selected between steps. If anyone can help, I'd appreciate it.

Select NOPATTERN SHOWHIDDEN
Select "Images Only" FILTER HIDEUNSEL SHOWHIDDEN DESELECTNOMATCH
Select ^[Ss]creenshot_.+$ REGEXP HIDEUNSEL SHOWHIDDEN DESELECTNOMATCH
Select ^.+_Google\.{file|ext} REGEXP HIDEUNSEL SHOWHIDDEN DESELECTNOMATCH
Select NONE

Try removing SHOWHIDDEN from all but the first line.