Dear Stata community

I am experiencing a problem regarding my difference in difference analysis.

I am looking at the effect of shareholder proposals on the performance of companies. However, some of my companies received shareholder proposals more than in just one year. Some of them even received shareholder proposals in 15 years of my panel data. Is there any way to still do a difference in difference analysis to find out the effect of these shareholder proposals? Also, it has to be said that ideally, I would like to analyze the effect time-lagged with different amount of years.

Thank you very much for your help.

Best regards,
Lisa