InfoPath Dev

I have spent a lot of time trying to find this solution and to my surprise, it doesn't seem to be a common question.
I have 2 repeating tables. 

Table 1 - each row represents a part and contains a part number field and an isRemoved option button field (amongst other information).

Table 2 - each row contains a drop down, which pulls in all the part numbers listed in Table 1.  If one of the part numbers is selected, then I wish to have the isRemoved option button field in Table 1 change its value to "yes", but only for the row that applies to that specific part number

Currently I have a rule set up on Table 2's drop down that if that drop down field matches the part number field in Table 1, then to set isRemoved (in Table 1) to yes.  But this sets isRemoved in all of the rows to "yes"...and I can't find a way to filter which row to apply this rule to.
Can you please help point me in the right direction on how to accomplish this?

Thank you!

This is a challenge in InfoPath. Your rule is going to set all instances of isRemoved because it is on a field outside of the repeating group. You have a few options. One is you could use a default value for isRemoved in Table1 - then you could use an XPath filter to see if any instance of the part number is in Table2 with isRemoved = yes. Would a default work here? or is this option a field the user needs to also be able to set?

I am not sure a default value would work for the isRemoved field, but I could do a filter on the partNum field in Table 2 to match the partNum in Table 1 and mark the isRemoved field for that specific row. Only problem is, I can't figure out how to filter that way.