yes it is possible... i have make this possible.. its sounds unbelieveable... but the biggest problem was for me to create a option to can see the balance from multisigaddresses without have all private keys... With many patience i have create a option to can trade between coins without have the fear that anybody can steal your money or can try to cheat....?
How its possible?
My decentralized exchange works because the nodeserver(Everybody the uses my Decentralized Exchange is automatically a node server) , you and your partner must sign the transaction with the private key... To make this process easily i have created and added many rpc commands with my algorithms and features to can easily build a exchange with java c++ etc... for any coin the have the same address version as bitcoin...
I have added many encryption algorithms settings to make impossible that anybody can sniff the packets... and still if anybody sniff the packets is useless then all priv keys owned youself...
the onlys decentralized coins are my bitcoin wallet and bitcrystal...
here but this projects takes many months and years ... its was very difficult and i always if anybody helpes me to supported my project...
https://bitcointalk.org/index.php?topic=966861.540http://bitcrystal.net/but its very difficult to add any coins to my exchange because you must have the knowledge and you must make a lot of changes in the source code of the coin... its takes many time