4th of July pool party and pregnant

Hi! Just found out I’m pregnant with baby 2! Like just about 4 weeks along. July 4 th is coming up and we go to our family’s house for a pool party every year. How do I hide that I’m pregnant? I know you don’t have to drink, but someone always asks “do you want to try this” “can I grab you another” “can I try yours” etc. the only thing I’ve seen is to bring cans , dump and fill with water. Any other ideas?!