Android tablet presentations: networking and equipment?
There are many possibilities for making this happen using different apps/services. But...kindly note: Playing a same ppt from single source on all three devices (one yours, and two for your clients) doesn't seems to be possible until they are connected to the same WiFi router (may be a offline router) but to be able to share screens using some screen-cast app or remotely controlling their presentations using team viewer sought of apps, the basic necessity is, that they all must be on same subnet. 

let me know if i can help you further in accomplishing your this task..

Hope that answer your query as of now..



Well dude, this part has nothing to do with your question asked above, Its just a little piece of advice from my side. 

Instead of taking pain of carrying three 10" devices and those too wont be collectively able to cater the need of more then 2-5 of your clients, i would suggest you to carry this device. As this definitely seems to be more useful for the kind of solution you are looking for. :)