The question is how to tell you without exposing myself to KE heat. Are the Frenchman, Flashgitz, or the elf's commlink running silent? I don't have their commcodes, but I'm hacker. I could get in my car and alert them silently via the Matrix. I'm thinking something like...
Matrix Perception to detect hidden commlinks/identify files pertinent to sending a message (like contact lists).
Use Hack-on-the-Fly to get a mark on an ally's commlink.
Use Control Device on the commlink to get it to send a message to itself, change its "desktop background" or equivalent action.
Does that sound plausible, GM?