Another congregation, yes, but not neccesarely another denomination.
Both Coral Ridge and New City Presbyterian (the church that Tchividjian started and came from) are associated with existing denominations (PCA and EPC respectively). My guess is that the members splitting from Coral Ridge will attempt to (re)align themselves with the PCA. Their dispute isn't with the denomination, rather they probably think the (new direction of) the local congregation isn't in line with the PCA's values.
They'd go EPC or some other Presbyterian/Reformed denomination before they'd go independent/non-denom.
How do you guys keep all those three-letter acronyms straight?