Salutations, fellow Zenners.

I am setting up a cart for a client that has four products. What she is looking to do in terms of shipping is as follows:

1. Individual-item purchases are shipped via USPS.

2. Multiple-item purchases are shipped via UPS.

3. On the multiple-item purchases, shipping is $3.00 for 2-5 items, and $5.00 for 6-9 items.

4. 10 or more would be "call for special ordering."

OK, with all of that, consider that I am still a bit of a rookie to Zen Cart, and absolutely green when it comes to shipping. Where should I start?

Any feedback appreciated, even it's a simple RTFM!