Unfortunately, you cannot avoid the tax splitting on the pension chosen to be split. Both the pension and the taxes paid on it are to be split for the same percentage as explained by the Canada Revenue Agency (CRA): "if the transferring spouse or common-law partner allocates 50% of their eligible pension income to the receiving spouse or common-law partner, 50% of the income tax withheld at source on that pension income must also be allocated to the receiving spouse or common-law partner."
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