To segment your mailing on say a range in the Last Donation field you could create various searches with the relevant criteria and load them into a mailing and segment them so you can use different templates asking for different Next Ask values.
1.Click Search Mode on the tool bar of the Contact Details form or Home Page
2.Click the RFM / Next Ask tab under Prospecting
3.Enter the Next Ask ID and/or Description and any other information – for example – Last Donation, Average Donation
4.Click into another field
5.Enter a Name for the Search, Click Save
6.Click Only You if you do not want other people to use this search.