There's an app note that speaks directly to this NXP AN10441 (attached) issue and I've used it several time with perfect success. Since the 2 pull-ups must be there for each side if separated you are only adding 2 small mosfet's to a design a BSS138 works well here and I've used 2N7000's with good results.
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AN10441.pdf (52.4 KB)