Complex sentence: Other states, like Kosovo and Montenegro, have adopted the euro unilaterally, but these countries do not formally form part of the eurozone and do not have representation in the ECB or the Eurogroup.
Split into simpler sentences: Other states, like Kosovo and Montenegro, have adopted the euro unilaterally. However, these countries do not formally form part of the eurozone and do not have representation in the ECB or the Eurogroup.