This time with better formatting < s >

Create a parameterized view of the current table

create sql view lv_Myview as select ... ;
   from CurrentTable where somefield = ?cSomeValue ;
   order by somefield

When a record from the another table is selected:

if not used('lv_MyView')
   use lv_MyView in 0 nodata
endif
local cSomeValue
cSomeValue = upper(alltrim(AnotherTable.FieldX))
*!* assumes you have an index on upper(SomeField) for optimization
requery('lv_MyView')
ThisForm.GridName.Refresh()