Long hold the contact in Textra.
Click the three dots and choose customize.
Click notifications.
Click the Android notifications button.
Scroll down and click advanced.
From there you can set them individually. On my old phone it was right in Textra's menus but I'm guessing newer versions of Android force the hoops.
Anonymous
It can be done, but it is not intuitive:
Long hold the contact in Textra.
Click the three dots and choose customize.
Click notifications.
Click the Android notifications button.
Scroll down and click advanced.
From there you can set them individually. On my old phone it was right in Textra's menus but I'm guessing newer versions of Android force the hoops.