Setup env parameter for array in config?

[musinit]

I need to setup the following yml struct (example):
shards:
-
user: "userA"
password: "passwordA"
-
user: "userB"
password: "passwordB"
userA, passwordA, userB, passwordB needs to be fetched from envs.

Are there any ways, how I can do this?
Something like this envs: SHARDS_1_USER, SHARDS_2_PASSWORD