pjaffe,
Open an Ink and a Freedom Unlimited.
The Ink is a business card, so everyone will get a unique number.
The FU, will earn 1.5 ppd (points per dollar).
For maximum points earning, everyone should have both cards, but use the FU mainly. When the FU becomes compromised, they use the Ink until you get them the replacement FU.
If that's too much work, just use the Ink.
Also, keep the UA card open for expanded saver availability.