Hi there is a pretty cool way to add attributes. The google methodology of UTM param can be forgotten and now I would focus on learning about Adobe campaign IDs. Internal and external.
If we look at logic that in this case it will be an External ID. then in the tracking ID setup the different attributes like this...
?ecid=EMAIL|ATTRlevel1|ATTRlevel2|ATTRlevel3... etc (i like pipe easy to filter against later.)
So examples of output report under external campaign IDs are then:
EMAIL|salesagent2|Customernumber45|Followup
EMAIL|salesagent34|Customernumber126|FirstTouch
etc...
Also learn about the power of SAINT classifications, very very powerful and very streamlined way of working with tracking IDs
Classifications
Done right you could associate on one pageview both internal and external tracking IDs involved on a page visit and eventual success event...
GLTU