MINAVISIBLE

MINAVISIBLE(rgeValues)
Returns the smallest value from the visible, non blank cells (including logical values and text).

REMARKS
* This function excludes hidden cells caused by AutoFilter, Grouping or that have been Manually Hidden.
* You can use the built-in MINA function to include hidden cells.
* You can use the user defined MINVISIBLE function to
* You can use the user defined MINVISIBLEIFS function to
* Similar to the user defined functions AVERAGEAVISIBLE, COUNTAVISIBLE and MAXAVISIBLE

For instructions on how to add this function to a workbook refer to the page under Inserting Functions