LINK function of a LIB

I want to link a single function of lib to a different location for load and run.

I have a slowmem section defined for all the other files, but i want to link e.g. the _printfi.obj  of rts55x.lib to another section.

The idea is:

   UNION
   {
        .slowmem: load > SDRAM, table(_slowmem_ctbl)
         rts55x.lib: _printfi.obj > SDRAM
   } run = SARAM

But this doesnot work. Any hint is welcome.

Micky