In OpenSim grids it is common to need to move things we have built from grid to grid. LIBOMV ( libopenmetaverse ) is a new tool for doing just that. It is a DOS Command Line (text commands and no in-world view) type program. So, you may want to look at Astra Viewer for a viewer tool for importing and exporting between grids (OpenSim Astra Viewer Review).
While Astra uses a HPA (Hierarchical Prim Archive) file type for exporting and importing, LIBOMV uses XML.
Chapter and Metaverse has a short tutorial on installing and using the tool. See: Moving Objects between Opensims. It is not as simple to use as Astra’s export/import tool.
I have yet to try the tool LIBOMV. Let me if it works for you.