Each MultiChain blockchain has a set of blockchain parameters which determine that chain's behavior, in terms of actions which are permissioned or non-permissioned. The one you want is anyone-can-connect. If you set this to true, then MultiChain nodes accept regular bitcoin-style handshaking (without nodes identifying themselves by address and proving they own that address), so any open source bitcoin wallet can easily be adapted to work with the network. The protocol is exactly the same – MultiChain just uses metadata within the rules of bitcoin's transactions format to represent assets (as well as permissions, streams, etc...)