Original: These 10 member countries had agreed to form a "Single Domestic Space" in which travelers would only have their passport stamped and have to submit completed, standardized entry and departure forms at the first port and country of entry.
Simplified: These 10 member countries had agreed to form a "Single Domestic Space" in which travellers would only have their passport stamped and have to submit completed, standardized entry and departure forms at the first port and country of entry.