Request for "macron below" glyphs

In several indigenous languages throughout Australia there are several words that include ḻ, ṉ, ṯ or ṟ characters to indicate a retroflexed consonant.

Unfortunately none of these are supported.

I would like to be able to use these characters rather than many string replacements to underline the character across a website like this one https://parksaustralia.gov.au/uluru/discover/culture/language/.