If you only care about appearance in all views and for documents - and are not at all concerned about scheduling the repeated elements, then you can do that in GDL. David Nicholson Cole had an example floor joist object, for example, that was stretchy and would repeat according to parameters within rectangular bounds - in the GDL Cookbook.
If you need individual elements so that they are scheduled properly, etc., then Grasshopper or a custom API add-on would be options.
But, I'm with Erwin... in general, it is easier/faster to just re-multiply. Your issue with not grouping: it's true that auto-grouping for some reason does not work with multiply... but all elements except the first are selected after the multiplication. So, just shift-click the first element so that they are all selected and cmd/ctrl-G to group them.
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