Hi,
I don't know what your store database is, so like that I can't answer you.
By default it is not something which will be possible, it will require some specific development and some custom plugin in order to create such bridge (for the hikashop part and also your store database part).
At this moment I can only recommend you to contact an external developer or some HikaShop partners.
www.hikashop.com/home/our-partners.html
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.