I would like to join 5 databases that contain the same columns. However I would like to create a new column with data that are equal in 2 or more columns

Question

I have 5 contacts reports that opened my company’s email shoots. The reports contain the same columns. I would like to join these 5 reports in 1 by just analyzing which client is in 1, 2, 3, 4 or 5 reports.

email_dia_do_trabalhador = read.csv("dia do trabalhador.csv", sep = ";", na.strings="", stringsAsFactors=T)

email_parceria_fronius_pieta = read.csv("parceria fronius e pieta.csv", sep = ";", na.strings="", stringsAsFactors=T)

email_voce_conhece_piep = read.csv("Vc conhece o piep.csv", sep = ";", na.strings="", stringsAsFactors=T)

email_voce_na_intersolar = read.csv("vc na intersolar com a pieta.csv", sep = ";", na.strings="", stringsAsFactors=T)

email_voce_no_summit_solar = read.csv("vc no summit solar.csv", sep = ";", na.strings="", stringsAsFactors=T)

First I read the reports files and thought about using the join_all(), however do not know how to make this analysis of customers who are in one or more reports.

dados <- join_all(list(email_dia_do_trabalhador, email_parceria_fronius_pieta, email_voce_conhece_piep, email_voce_na_intersolar, email_voce_no_summit_solar))

How do I create a new column with this analysis if a customer is in one or more reports?

NOTE: The columns of the reports are: email, First name and Last name. These customer data do not vary from report to report.