If you want to introduce a new container on the right side, simply leave the title empty.
Keep in mind that the tabbing order will not go from left to right, top to bottom, but rather (within each container) from top to bottom, left to right. After all, it's just a SimpleForm ;-)
Check out this example in action (make sure to run it in full-page mode to see the fields displayed correctly due to its responsive nature):
sap.ui.controller("view1.initial", {
onInit : function() { }
});
sap.ui.xmlview("main", {
viewContent: jQuery("#view1").html()
})
.placeAt("uiArea");
<script id="sap-ui-bootstrap"
src="https://sapui5.hana.ondemand.com/resources/sap-ui-core.js"
data-sap-ui-theme="sap_bluecrystal"
data-sap-ui-xx-bindingSyntax="complex"
data-sap-ui-libs="sap.m"></script>
<div id="uiArea"></div>
<script id="view1" type="ui5/xmlview">
<mvc:View
controllerName="view1.initial"
xmlns="sap.m"
xmlns:l="sap.ui.layout"
xmlns:f="sap.ui.layout.form"
xmlns:core="sap.ui.core"
xmlns:mvc="sap.ui.core.mvc">
<f:SimpleForm
maxContainerCols="2"
editable="true"
layout="ResponsiveGridLayout"
labelSpanL="4"
labelSpanM="4"
emptySpanL="0"
emptySpanM="0"
columnsL="2"
columnsM="2">
<f:content>
<core:Title text="A Title" />
<Label text="1st label" required="true" />
<Input value="Blah" />
<core:Title text="" /> <!-- empty title so it looks like this container belongs to the left one -->
<Label text="2nd label" required="true" />
<Input value="Blah" />
</f:content>
</f:SimpleForm>
</mvc:View>
</script>