So you actually have the roadwarriors on the same openVPN server instance than the site-to-site connection?
I wouldnt do that.
Keep them separate.
One instance in PSK setup for the site-to-site.
One instance in PKI setup for the roadwarriors.
Like this you can use routes for the site-to-site and pushes for the roadwarriors.
If you keep them together it gets nasty with client specific pushes and you'll never have satisfactory client separation.
This was a very recent similar problem:
http://forum.pfsense.org/index.php/topic,16028.0.html