Rf based wireless trigger

i am making a wireless trigger to trigger studio flash. for this i am using 8051 controller rf module, encoder ht12e ,decoder ht12d.

transmitter side: i am using encoder with at89c2051 rf transmitter

receiver side: using decoder with 8051 rf receiver

now the requirement is the if at a place there a 3 studio flash is installed. they should NOT b trigger by same remote. the flash should b trigger from its own remote trigger
ans: for this i am using different address bit of encoder decoder to differentiate one from other..! but one of my friend have already worked he is saying that it is not possible because your module are working on same frequency the other remote data will clash and will trigger other flashed even if the address bits are not same..!

kindly suggest something..!
is it true.??.the address bit wont effect even if they are not matched still it can trigger other receiver because theory say that till the address bit of encoder decoder not match the communication is not possible..! so should i go on or use some other concept..! or is it possible to work on different frequency..! i have already worked on rf but not in multiple receiver concept..!

My requirement is that i want to trigger flash for example if two studio flash are installed in one hall..they should not b trigger from only one transmitter remote .they should be only trigger from their respective remotes.for example say flash1 remote 1, flash2 remote 2, the flash1 should not b trigger from remote 2 and the flash 2 should not b trigger from remote 1..! so here how can i use the different frequency form your module..!