Be really careful with such services. Even Escrow My Bits which was a well known escrow service has done lately several scams and their multisignature escrows are having a lot of bad reviews.
I suggest finding some trustworthy escrow in this forum. SebastianJu is one member who I knew was offering such service but don't know if he offers it anymore. Here you can contact him :
https://bitcointalk.org/index.php?action=profile;u=18640Here is his thread:
https://bitcointalk.org/index.php?topic=1102721I hope this helps.