I think the problem is that RP groups on dA are either dead, not running properly or there is a lot of drama going on in the playerbase. The 'glory times' that lasted until two or three years ago are over and most of the serious RPers moved on to either private RPs or other websites (tumblr RP, toyhouse, etc...).
The experience I made with RP groups lately is that they unfortunately are stuffed with hyenas, so as good artist you get a lot of people that want to RP with you right away but you can feel in most RPs that they are pushing to get your OCs into bed and get into a couple with them which also causes drama within the group rather easily (I seriously had someone accusing me of cheating on their OC because I RPed with someone else and our OCs hang out in town together while all I ever did with the other person was crossing a forest together... it was crazy...) Not sure what you are looking for, but if you are more into storydriven RPing, adventuring, developing relationships over a long time, etc maybe checking privately with RPers you enjoy playing with is the better idea. My friends and I created our own 'RP Group' just for ourselves so we had a world to RP in together and that's working quite well. But that is just my personal opinion. o3o)/