Formula calculation in a Shared Excel File
 

I have a Shared excel workbook which has data entered though the month by
multiple people, in this file I have a number of formulas producing data
about the entries.

The issue I am facing is that when any of the users open or save the new
entries the file takes quite a while to re-calculate the formulas. I know I
can use the Calculation tab in options to manually calculate the fields but
this only works at an individual level rather than in the actual workbook and
it also will apply to evey excel file we work on.

Does anyone know a solution to have a selected range of cells with formuals
only to re-calculate when requested?
--
Cillian