Help Joining 3 worksheets using common fields using IF & VLOOKUP formula

Hi, I need some help with joining 3 worksheets that are connected to each other by common fields. If you look at the attached image you will see that I have 3 worksheets; Opportunities, Quotes, QuoteDetail.

I need to get the Currency displayed in the Opportunities worksheet. The way I need to do this is to first match the crmOpportunityID from the Opportunities worksheet with the crmOpportunityID in the Quotes worksheet. Then I need to get the corresponding Quote ID from the Quotes worksheet and match that with the Quote ID in the QuoteDetail worksheet. Then I need to get the corresponding Currency value and display that in the Opportunities worksheet.

I tried to do this using the following forumla which seems to work until there is not a corresponding crmOpportunityID in the Quotes worksheet?

=IF(B2=Quotes!A:A,VLOOKUP(Quotes!B:B,QuoteDetail!A:B,2,TRUE),"")

Any suggestions would be greatly appreciated.
Thanks
Steve