Having two colors...

[Massimo26558118juzy]

I have two RGB codes. Is it possible with Adobe Color to find a third one that matches?

[syed_mehadi]

you can select desired harmonical combination for your colors, set the first color as base color.

once done, you can switch harmony to custom, select second desired color and remaining three will be nearly matching in that harmony?

[Bob_Hallam]

You can harmonize with a third color but not match.  Look at Triads for this feature.