Custom editors on a form

Hi, I am in the process of developing an 'AND', 'OR' editor on a form. The idea is, a) Pick up the list of objects displayed on a grid. b) Develop an editor (on a form, probably) to  'AND' or/and 'OR' the object values c) assign the concatenated value to a field on the form. While I am clear about (a) and (c), I would like to know if you have some suggestions for (b), an editor on a form for 'AND'ing or/and 'OR'ing. Regards, Alexis.