How can I add another row to a Multi-Row Expression?

Question

I need a little help modifying an expression

Current Scenario

I have a data set that includes Name and cost type (CT) and amount for a given year (2017 $).

For any cost type Bs, I need to add B to A.  (B is always negative.)  I use the following expression with the Multi-Row Tool set to create new field.

if [Row+1:CT] = 'B' then [2017 $] + [Row+1:2017 $] else [2017 $] endif

NameCT2017 $JeepA555G-WagonA1800G-WagonB-100G-WagonC200HMMWVA800HWMMVB-400UnimogA700

Question

Now I need to add E to the expression.  Like B, E is always negative.  But, its still A+B+E.

How do I mod the expression to include E?

NameCT2017 $JeepA555G-WagonA1800G-WagonB-100G-WagonE-500G-WagonC200HMMWVA800HWMMVB-400UnimogA700

hellyars · Accepted Answer

I think I got it.  Hopefully it will translate to the real data/worklow.

if 
[Row+1:CT] = 'B' and [Row+2:CT]!='E' then [2017 $] + [Row+1:2017 $]

elseif 
[Row+1:CT] ='B' and [Row+2:CT] ='E' then [2017 $] + [Row+1:2017 $] + [Row+2:2017 $] 
else [2017 $] 
endif