Do theyyou want them to be able to jump to ANY star or just some specific stars?
In the latter case, you have Mass Effect's mass relay.
The basic rule is: You can only "jump" from relay to relay.
Hence, you can't jump to a star system that doesn't have a relay built yet. This makes FTL not viable for "exploring" but once some colonies have been established in a system, they could start building their relay to be connected to the "relay network", so the FTL trading and massive inmigration may start.