f the barcode that you are scanning is all code 39. then we cannot set the rules due to there is no unique criteria to separate the rule set.

If you have three different type of barcode. E.g. code 39 is always scanner first then code 128 at second and last qrcode.

Then you can set the rule, You need to add (Filter criteria section) when creating the rule.

So in this type of configuration, the rule 1 will always apply to code 39.

2nd option is, to maintain all code 39 but you need to have a special criteria.
Like barcode that need to scan first always starts with alphabet (A) second starts with alphabet (B) and last barcode starts with alphabet (C)