I'm not entirely well versed in how Redis works, but I have an idea that it probably makes the most sense to have the 3 craft sites I have running on the same server, have 3 different redis databases assigned to each?
Is there a way to do so, like in general.php
or db.php
As in
"site-one.com" => {
'database' => 0,
},
"site-two.com" => {
'database => 1,
}