Clear URL ( without slash ) - combination of category and brand

[kuracina]

Hi,

my actual setting for categories is:
www.domain.com/brand/category

Im looking for more SEO friendly URL without slash.
www.domain.com/brand-category

My problem is that in my shop is many brands ( thousands ) and i dont know how to determine that first word is brand ( many brands have more words in name ) and other is category.
Its works over .htaccess

I think that can works if i will test first words with all brands in database viac PHP script.
I scare that website will very slowly in loading.

Can you help me ?

Thanks a lot