1) Create 2 DataSource steps, both referring to the same file but different sheets and each with their corrsponding properties (start_date and end_date)
2) Refer to these 2 values using standard property-expansion in your request, ie something like:
If you are not using soapUI Pro you will need to compile your scripts into a standard java library (ie .jar file) and add that file to the classpath by putting it in the bin\ext folder..
hmm.. maybe you could define one DataSource for each sheet (both using the same excel file), and then refer to the corresponding DataSource steps for the start/end_date values?
if you want to assert all blocks individually you will have to create one assertion for each block, otherwise you can create just one assertion with the entire xml containing all 200 blocks!?