Appear as offline function?

So many people on my friends list... so many people that i like to play with sometimes but like... dont always want to play with..

I dont want to be all like "Dude im trying to go solo here, i prefer solo right now" because people take that to mean some sort of insult...

i'd like to appear as offline to my friends list, or in a perfect world, to subcategories of my friend's list at certain times, while i practice new things, or play around with strange builds i see on youtube.

If im not at least mastery 4 on a champ (Just by number of games and the comfort of that) i dont want to play that champ around people i play with, why? Because if it goes horribly wrong i feel bad enough with pugs.

TL;DR Rito please privacy options