no, server validations wont be able to do this, you will need to hand code it.
add a hidden element in the repeat region that will store the maximum number of tickets for each line.
outside of the repeat region, add another hidden element. the repeat region uses an incrementing number on each element name. Use the variable for this incrementing number as the value for this hidden element. this will pass the number of lines that the repeat contains.
use that in a loop to compare the quantity field with the max quantity field.
