Solution for classroom audio

[goNativeEnglish]

I run a language school and I use tablets and google home minis to do 'listenings'. It works ok, but the teacher has to 'mirror device' each time to cast to the speaker and there is a slight delay, which is annoying.

If someone could suggest a solution that would mean the tablet casts permanently to the google mini and eliminates the delay I would be grateful.

GoNative English