If you have all instruments, it makes this much easier, even more so if you have a friend in the same situation.
Due to the dying online community in this game, combined with the addition of the ability to have multiple band members playing the same instrument, you will find this a hard achievement to get legit.
Best to set up a boosting session and coordinate with a partner.
Simply set up each of the instruments (Guitar, Bass, Drums and Vocals) on your team (only your main profile is required to be signed in, the rest can be guests) and search online for a Band v Band at the same time as your partner who should have an identical setup.