I think the main problem is how to aggregate the 100 rows of data to pass in one tSOAP. If you can do that, then calling the tSOAP only for every 100th row is quite easy e.g.
(construct your SOAP call aggregating the 100 rows of data) --> tFilterRow advanced: Numeric.sequence("s1",1,1)%100==0 --> tSOAP --> (reset your SOAP call construct to start with the next set of 100 rows)
Don't forget OnSubjobOK --> tSOAP for the remaining data rows in excess of a multiple of 100.