DP83867CR: Unused Differential Pairs in 100BASE-TX Mode

Tool/software:

Hi Support,

When a 10/100/1000 PHY operates in 100BASE-TX mode, electrically, what does the PHY do with the two unused pairs?  Does it float or ground them?  The reason I ask is because the product will have five 1000BASE-T  ports (PHYs are integrated in the Ethernet switch), plus one 100BASE-TX port, which will use a DP83826I PHY.  I would like to use 6 of the same jack with integrated magnetics for 1000BASE-T.  Since the DP83826I only connects to two pairs, I am wondering what to do with the two unused pairs?  I figured asking the question of how the DP83867CR treats those signals (TD_P and TD_M of two pairs) when operating in 100BASE-TX mode, would answer the question of what I should do with those unused pins on the jack.

Here is a screenshot of the jack with the unused pins circled:

Thanks for the help.

Regards,

Greg