SAOP UI 2.5 load concurency problem... need to send unique value to each thread

Hi,
SAOP UI 2.5 load concurency problem... need to send unique value to each thread--plz suggest me solution in SOAP UI 2.5.1 onlt.....


I have a scenario where i will hv to run two apis one after another. And i will have to pass a value to first api by using properties..for single run it is working fine but when i put under load for concurrent runs it has failed in 95% of runs. bz i will ahve to pass uniuqe vale. once the first thread takes thta value..the remaining ones are not able to fetch those..so these apis are failing.

can u suggest me a solution