Select - options in at selection on field

Hi ,

i have a field on the selection screen where i am giving range of values .

using at selection on field , i want to check for all the vlaues in the ranges whether they are vaild or not .

ex : for plant : 100 -200. (range ) .

want to check whether the values from 100 to 200 are valid .

Thank you in advance . let me know please .

Regards,

Ry