don't feel too bad yet or give up-- you merely just need a terminating adapter.
http://www.ebay.com/itm/310390365299
this one has a termination block and support for both 50 and 68-pin... I'm going to hope this works for me.
There's also another which has actual active termination soldered on the board, but it means it has to be the last device in the chain (not a problem in your situation!) but it costs a bit more and i didn't go for it.
http://www.ebay.com/itm/111079569749
there's also a couple of people here on 68kmla that build and sell terminating adapters.