EdMan196 is correct there is no
defacto way to move multiple objects "simultaniously".. that said....
There are a number of decent ways to approach this, the best IMO is if you are using a "subgrouping" approach you can map a temporary grouping from a centroid (say the cursor) and draw using the deltas from the mapping added to your cursor displacement.. this is probably the best approach as it will allow for the object to still have "behavior" on their own and lets you treat the "selection moved" vector as a perturbation rather then explicitly.
(using this approach you could get the objects to still move relative to one another inside your selection group if you so desired)
alternatively you could look at applying a transform, which might help clean up the approach from a code perspective but will be slightly slower in execution.