update specific feed via cronjob

/usr/bin/curl –silent https://yoursite.com/?update_feedwordpress=1

I have more than 200 feeds, which when i do update_feedwordpress it takes a long time, more than 15 minutes, then the first feeds do not be updated within that 15 mins. i need to update a specified feeds. how it is possible?

i have the same issue, please someone help