HI Joel,
I apologise in advance for not knowing how familiar you are to MSMP and BRF+, but I will give you some basic ideas of what requires to be done.
1) Create 2 paths, one with the 2 stage approval, the other with the single stage.
2) Within your ARM custom initiator (which you will need to create, as SAP standard delivered initiator does not cater for EAM ID provisionging requests), utilise the conditions "request type" and something like "role connector" (I am unsure if EAM id's use the same field). In the BRF+ decision table, you need to have your 2 conditions defined in 2 rows with each one having a distinct trigger value/result.
3) Back in MSMP, configure the custom initiator to the Access Request process flow and then map the routing result. Finally activate the workflow.
Majority of the configuration is easy, but the only doubt I have is with the EAM specific attributes being available as condition columns in BRF+ For Access Request purposes (Never had to implement your scenario as such but I may have a look during one of my quiet days)
all the best.