Drop-down list returning combined value depending on column

As per new screenshot, I want to create a drop-down box where I can choose any of the categories that have been entered in the table, and it will show the combined value beside it (F2 and F3). Example: E2 is a drop-down, I can choose Sale or Salary (only two entered so far for Income) and Sale will show 1250 in F2.

E2 and E3 are just where I want the clickable drop-down lists, they don't need to say Income/Expense respectively. Challenge for me here is in having each one only allow its type, so Income has only items with a value for Income and ignores Expenses, and vice versa.

I need the simple quadrant for visual necessity, I will use the idea as part of a larger presentation spreadsheet, so pivot table I don't think is suitable for this scenario I think.