Set number of available avatars by post count?

[Noosphere]

I want to set up my avatars with various “tiers,” for example

- Users with 100 posts or less can select from a set of 25 avatars
- Users with 100-500 posts can select from the original group of 25, plus a 2nd group of 50
- Users with 500-1000 posts can select from the first two groups, plus a 3rd group of 100
- Etc.

If there’s an option in the Admin CP that does this, I’m totally missing it and am going to feel damn silly ... but I’ll deserve it, so go ahead and mock.

Otherwise, I’m certain there must be a mod (3.8.2 compatible!) out there that accomplishes this arrangement, but so far I haven’t been able to track it down. Can some kind soul point me in the right direction?

Thanks ...