Yes it is. What i do, is to seperately import the Items that i want to merge to one Item. Then i hit Ctrl+C in the Window of one of the Items, to copy the Mesh, go to the Window of the other Mesh, hit Ctrl+V to paste it in that Window and then i click on the round green Icon with the Checkmark Symbol, in the up popping Window. Now you can export the new merged Mesh as one.
