A crossblooded sorcerer multiclasses as a bloodrager. According to the rules for hybrid classes:
Parent Classes: Each one of the following classes lists two classes that it draws upon to form the basis of its theme. While a character can multiclass with these parent classes, this usually results in redundant abilities. Such abilities don't stack unless specified. If a class feature allows the character to make a one-time choice (such as a bloodline), that choice must match similar choices made by the parent classes and vice-versa (such as selecting the same bloodline). The new classes presented here are all hybrids of two existing core or base classes.
Must the character take the crossblooded rager archetype of bloodrager in order to match the bloodlines, or must they select only one matching bloodline, or is something else true?