You need to group objects together that you want to transform about a single point, select the group they are in and set your motion on the group - you can reposition the group's pivot axis by selecting the group, hitting ,, move pivot axis, hit < insert> again. otherwise, if you select multiple objects, maya assumes any transforms you do you want based on each objects individual pivot axis - it just displays the last one selected as a reference. you can group the group also, and therefore have several different pivot points for different motions.. - to easily select the group, select a surface, and hit the up arrow until the desired group level is selected.