For sure you'll need a set of metric allen wrenches and small metric box (or perhaps open-end) wrenches for each bike. (Sears has a nice set of small "ignition" wrenches - check the sears site for info).

Then sit down with each bike, and just check every nut, bolt and allen fastener. Keep the tools that fit with the bike-specific toolkit.

Those will take care of 99% of the "on the road" issues.

Next, decide what you want to be able to repair on the road... perhaps you'll want hub wrenches and a chain breaker; perhaps not. Up to you! Ditto chainwheel bolts, etc.

Check the limit screws on both deraillers -- include a screwdriver that fits.

Bingo; you have your bike-specific toolkits.

Every bike is different so it is hard for others to be specific.

Hope this helps.... and I hope I didn't misunderstand your question.

Tom in SoCal