As you are likely aware, the INDIRECT() function can be used to construct/convert a text based representation of a cell or sheet!cell reference to a usable cell/range reference. However, this native function does not work with external references.
There is a widely known set of Excel functions in the free MoreFunc Excel Add-in XLA that contains a derived INDIRECT.EXT() function that will grant the same construction/conversion to an external address and there is a version compatible with Excel 2010.
Be very careful of downloading this set of library functions as there are fake/hacked versions cropping up around the Internet. I believe the following is safe for version 5.05.
MoreFunc version 5.05 from FreewareFiles.com
For the record, I personally feel that the INDIRECT.EXT() should only be used in absolute necessity where no other native method would do. It should not be used as blanket 'fix-all' to poor worksheet/workbook design.