Can we remove volumes from XIO CG when there are multiple snapshot sets associated with it?

Hello,

Can we remove volumes from  XIO Consistency Group when there are multiple snapshot sets assiciated with it. There are 15 devices altogether out of which 4 are unmapped. I want to remove these 4 from CG. There is a message displayed - 'Removing volumes from CG will cause a loss in cross consistency of further snapshots. Proceed?' Is this message for existing snapshots or future? What will be the impact? Will I not be able to restore from the snapshots taken out of the CG?