Hi,
First, you have to create a shipping zone for your EU countries and include the countries should be into.
Create another zone with all other countries (a no EU countries zone).
After that, you have to create a manual shipping rule which will have some restriction (price and zone). This one will be "free".
When the free shipping, you have to edit your current shipping rules in order to put a price restriction.
You might need to duplicate some for the zone. One with the EU zone and max price restriction. The other with the "no EU" zone restriction.
If the zone is not EU, all "no EU" shipping rules will be use.
If the zone is EU, all "EU" shipping rules will be use and if the price is above 100 euros, only the "free shipping" one will be displayed.
You can also make simple rules if you don't want to hide automatically the shipping rules.
Regards,