Is there a way to specify kerning for a character before a space?

The reason I ask is I am making a duospaced font, so I can't use the monospace option. For characters that don't cover the whole tile, it is a problem because for example in Pixelfont the dot character is 3 pixel wide (single pixel centered in a 5px tile) instead of 5:

The trick it to add 2px between the dot and the next character. It works fine, expect I found no way to specify "increase kerning by 2px between a dot and a space". So with most ponctuation followed by a space, kerning is narrower than expected:

(top line is with monospace option, bottom one is my attempt at duospace)

It is tricky. In the kerning table we could escape it like "\  " (backslash space) but that would be hard to read.
Or perhaps "\s"? As in regex it "matches whitespace".

Another way would be to use a double character, something legible like "!!"

I'm not sure it would be practical in glyph images, that would probably require some color coding, like "red indicates width".