use of 2 close rf transmit/receive modules

is it possible to use two 433 Mhz RF modules at same place..
i am designing a project with two 4ch rf modules (without a micro-controller), tried setting addresses with DIPs.

nothing seems right, only on pair is functioning at a time..

transmitters are at two different locations.. both receivers at the same location
may be the because of the interference. Is there any alternative to this issue, or should i change the second RF module to 315 MHz or others..

concept..
each room consists of two 4ch rf modules, it should not interfere with the other rooms rf module

please advice

A receiver gets confused if it picks up two simultaneous broadcasts on the same frequency. It may lock onto the stronger carrier, if you're lucky.