Is there a workaround to add tags to journal entries?

I'm fully aware that you cannot add tags to journal entries in QBO.  However, it would still be helpful if I can find a work around to this issue. 

Often I will receive a monthly statement from a supplier, and I will pay the monthly statement in one lump sum instead of paying the hundreds of individual invoices one by one, which saves an immense about of time.  I then use a journal entry to split up the expense categories. 

So let's say I pay a statement of $1000. 

• $700 is for Materials
• $300 is for Tools

So I create a journal entry for $700 to the Materials Account (DR) and $300 to the Tools Account (DR) and then $1000 to the Checking Account (CR). 

But let's say I want to track $500 of the Materials to a specific job. Normally I would just add one of my job tags to an expense when it's a single invoice I've paid. But in this case I've paid for multiple invoices at once and only a portion of them (in this case, $500 worth) apply to the specific job I want to track. 

Can I also create an expense for $500, apply the tag there and then try to match it with the journal entry? Or is there some other workaround?  

Thanks in advance!