No social security if the S Corp pay her through you in subcontr

Let your S Corp pay you in 1099 and then you pay her in as your 1099 contractor. Then that 3w becomes your deductible cost and hence no tax to you. And that 3w is directly from you to her and does not required to pay social security.

Either way, it is to justify her worth of the 3w payment, which is usually very difficult in front of IRS, which is taking fair market payment test.