A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
By dynamic I'm going to assume that you want to place the start and stagger in separate cells somewhere and have the formula adjust as per those values.
The formula in D2 is,
=IF(AND(COLUMNS($D:D)>=$A$2,NOT(MOD(COLUMNS($D:D)-$A$2,$B$2))),$C$2,"")
... which can be filled right as necessary. It should be able to be filled down as well, but I'm not sure how your own worksheet has the referenced cells laid out.
I've uploaded the sample worksheet here. Look towards File in the upper left for download options.