Trying to match values across multiple sheets

[coxyada]

I have a spreadsheet with data on 3 separate tabs. I don't if I'm trying to do too much with the spreadsheet, but this is what I need:

Sheet1 has columns with sections, products, and planned buy/sell dates.
Sheet2 has a column listing non-business days.
Sheet3 is a calendar that has rows which match the sections of the product, product number, and value from sheet1, and has a 7-day calendar.

I need a second if statement (or something) added to the function below. This function matches the data on sheet1 with sheet2, matches a buy date on sheet1 with a calendar date on sheet2, and inserts "BD" if its true.

=IF(COUNTIFS(BySection!$E:$E,$A4,BySection!$B:$B,$ B4,BySection!$C:$C,$C4,BySection!$F:$F,D$2),"BD"," ")

I need to also insert "SD" for a slightly different set of criteria:

If the product information on sheet1 matches the product information on sheet2, the Sell date matches the calendar date on sheet2 and it is not a non-business day (listed on sheet3), then put "SD" in the cell.