Can we make multiple RF device communicating same time with one master?

Hi Friends, I am doing some project on my arduino UNO with RF module at 433MHZ. I want to design multiple slave and single master to communicate different parameters. Means there are few conditions on which I want to send info to master immediately, but as there are many such parameters I am using multiple slaves, and I cant guaranty that two of those parameter cant set at a same time. so if two slave transmit message to master how to deal with this how to get both message? I am not using two different frequency RX or tunable module, again if I make master to make inquiry and slave to respond then it will again not vise as we dont no when will condition get true and I cant drain my battery continuously for no output. I also read some packetization process that could make it possible but I didn't understand how to do so! Is there any way to solve my problem? Thanks. Yatin

If you use cheap RX and TX modules, then it will be like many remote controls and older home alarm systems. They send a packet multiple times and hope that the Master receives it. For transmitting for example the room temperature every few minutes, it will be no problem to miss a few.

If you use transceivers, then it is possible to transmit data and the Master returns and acknowledge that it has received something. The RadioHead use that. http://www.airspayce.com/mikem/arduino/RadioHead/ The RHReliableDatagram option makes sure that the data is received.