Bridges operate at the datalink layer level and are usually indifferent to
network protocol. Routers operate at the network layer level and route only
specific protocols.
DEC does have bridges that "routes" IP, as do Cisco, CableTron, Ungermann-Bass,
Redix, NCS, ACC, and so on. Be aware, however, that some of the older bridges
may not pass both 802.3 and Ethernet packets. If you want to isolate the
network segment from the backbone, yet route IP and AppleTalk packets, Cisco is
one example of the many companies that can provide this support (product
descriptions are on AppleLink). They're among many developers of products
sometimes called "brouters" or bridge-router hybrids.