Oh, that's ideal for you then - she's already had the same idea. Play along and make sure (non-verbally and by implication) that the dynamic is the friend meeting the guy, and the target meeting you.
Obviously you have to adapt to your situation, but if I was in your position I'd text something like "great, hopefully (guy) and your friend will get on really well" (adapt this to fit your style).
Once you're in field, try and steer conversation so that the friend and the guy end up in a seperate conversation and you and your target are talking mainly just to eachother. Captive audience
What setting are you meeting them in? Club/Pub?
If so, there's a lot of opportunity, once you've established the two-part group dynamic, to lead your babe off to get a drink with you and seperate out. Keep your eyes out for when you can do this.