Frank,

You seem to have understood the requirement pretty well and come up with a similar solution to the one I had hit on ie doing separate mailmerges and joining them together somehow. Just in case I/you didn't understand the other I will try to give an example.

A letter to a person containing
1) A list of a number of object that they have requested.
2) A list of a number of objects that they might want.
3) A list of objects that they must have.

User defined text would appear between each of the lists and the lists could be in any order. And if possible the objects themselves could be described in different ways (ie some times with size and/or colour sometimes not).

Does that give a clearer example of what I'm trying to achieve?