Relate more than one entity in a mail template

Hello, I am new in suiteCRM and I would like to ask for help in something that I cannot solve, I created an email template and in that I have 3 entities in which I assign variables in the email template are: Account, Contacts, Invoice, but when I am going to send an email He only allows me to choose a relationship and depending on which one I choose, he replaces the variables of the email template when sending

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In the Related to part: he only lets me select 1 and in that case he replaces the variables of that table but in my temple I have 3 different tables, my question is is there a way to relate more than one entity or is it not possible?


Thank you very much in advance