recommendations for indoor (museum/arena) comms

Hey guys, I know this isnt a question regarding HAM.. so I apologize for that... But I couldnt think of another community that I could ask, since my knowledge of radio comms is so limited.

We run a non profit gaming convention, and we were looking for an affordable comms option for contacting one another across a pretty large INDOOR area. We bought some radios that served us in a less enclosed space.. but we have moved venues, and the block structure and range seems to be impeding our ability to reliably communicate.

I wondered if anyone could recommend an affordable (I am almost positive there will be no cheap options. lol.. but I had to ask) option for a few handesets, that we could find repeaters, to strengthen the signal, so we could stay in contact... or a more powerful out of the box solution that wouldnt require repeaters.

Again, I 1) apologize for the non HAMmy question and 2) for my general lack of understanding of radio comms, harware and verbiage. To say I have a basic knowledge in this tech would be giving me too much credit. :) We all have cellphones, but we end up missing a lot of messages on them.. so we wanted a better option if there is one.