Change event when dropdown selection changes

I have several events that need to be executed based on the users selection in a drop down box.  The form has 4 subforms which are simple one row tables.  The drop down selections are model numbers.  If the user selects model 1, subform 1 and 2 should be visible only.  If the user selects model 2, only subform 3 and 4 should be visible.  If the user selects model 3 all four subforms should be visible.  If the the user selects model 4 all subforms should be invisible.  I created each of these actions in the dropdown field's change event.  However, there is something missing in my code between each event because when I change the model in the drop down box the previous selection's event is still there.

I've tried several attempts using:

1. this.rawValue = xfa.event.newText;
2. xfa.host.resetData();
3. DropDownList2.setItems(myObj[this.boundItem(xfa.event.newText)]);
4. this.setItems(EngSalesModel)[this.boundItem(xfa.event.newText)]; etc.

But cannot get them to work.  Here is a snippet of my code from my form:

if ($.boundItem(xfa.event.newText) == "1") {

  oTargetField = this.resolveNode("TEF");

  oTargetField.access = "readOnly";

  oTargetField = this.resolveNode("TEO");

  oTargetField.access = "readOnly";

  this.resolveNode("TEF.TEFtable1.TEFRow1.TEFModel").ui.oneOfChild.border.fill.color.value = "192, 192, 192";

  this.resolveNode("TEF.TEFtable1.TEFRow1.TEFmohr").ui.oneOfChild.border.fill.color.value = "192, 192, 192";

  this.resolveNode("TEF.TEFtable1.TEFRow1.TEFPrice").ui.oneOfChild.border.fill.color.value = "192, 192, 192";

  this.resolveNode("TEO.TEOtable2.TEORow1.TEOModel").ui.oneOfChild.border.fill.color.value = "192, 192, 192";

  this.resolveNode("TEO.TEOtable2.TEORow1.TEOType").ui.oneOfChild.border.fill.color.value = "192, 192, 192";

  this.resolveNode("TEO.TEOtable2.TEORow1.TEOMoHr").ui.oneOfChild.border.fill.color.value = "192, 192, 192";

  this.resolveNode("TEO.TEOtable2.TEORow1.TEOPrice").ui.oneOfChild.border.fill.color.value = "192, 192, 192";

}

txtSelected.rawValue = xfa.event.newText;  

if ($.boundItem(xfa.event.newText) == "2") {

  oTargetField = this.resolveNode("TEF");

  oTargetField.access = "readOnly";

  this.resolveNode("TEF.TEFtable1.TEFRow1.TEFModel").ui.oneOfChild.border.fill.color.value = "192, 192, 192";

  this.resolveNode("TEF.TEFtable1.TEFRow1.TEFmohr").ui.oneOfChild.border.fill.color.value = "192, 192, 192";

  this.resolveNode("TEF.TEFtable1.TEFRow1.TEFPrice").ui.oneOfChild.border.fill.color.value = "192, 192, 192";

    oTargetField = this.resolveNode("TEO");

  oTargetField.access = "readOnly";

  this.resolveNode("TEO.TEOtable2.TEORow1.TEOModel").ui.oneOfChild.border.fill.color.value = "192, 192, 192";

  this.resolveNode("TEO.TEOtable2.TEORow1.TEOType").ui.oneOfChild.border.fill.color.value = "192, 192, 192";

  this.resolveNode("TEO.TEOtable2.TEORow1.TEOMoHr").ui.oneOfChild.border.fill.color.value = "192, 192, 192";

  this.resolveNode("TEO.TEOtable2.TEORow1.TEOPrice").ui.oneOfChild.border.fill.color.value = "192, 192, 192";

    oTargetField = this.resolveNode("MF");

  oTargetField.access = "readOnly";

  this.resolveNode("MF.MFTable3.MFRow1.MFModel").ui.oneOfChild.border.fill.color.value = "192, 192, 192";

  this.resolveNode("MF.MFTable3.MFRow1.MFPrice").ui.oneOfChild.border.fill.color.value = "192, 192, 192";

  this.resolveNode("MF.MFTable3.MFRow1.MFmohr").ui.oneOfChild.border.fill.color.value = "192, 192, 192";

    oTargetField = this.resolveNode("MO");

  oTargetField.access = "readOnly";

  this.resolveNode("MO.MOTable4.MORow1.MOModel").ui.oneOfChild.border.fill.color.value = "192, 192, 192";

  this.resolveNode("MO.MOTable4.MORow1.MOType").ui.oneOfChild.border.fill.color.value = "192, 192, 192";

  this.resolveNode("MO.MOTable4.MORow1.MOMoHr").ui.oneOfChild.border.fill.color.value = "192, 192, 192";

  this.resolveNode("MO.MOTable4.MORow1.MOPrice").ui.oneOfChild.border.fill.color.value = "192, 192, 192";

}

Any help would be greatly appreciated.  Thanks.