How to blur the eroded edge only?

In Fusion, I see that I can either blur (node Blur) or erode (node erode/dilate). I need to blur only those eroded edges, so the blur doesn't affect the rest. In Nuke I would use the "Erode (blur)" node, how can I achieve the same effect in Fusion. I don't mind combining several nodes.

When it comes to Fusion I would recommend watching anything by Simon Ubsdell. His knowledge is deep.
Somewhere in this five parter is a way to do exactly what you’re asking. Isolating and edge and blurring it. It also may be under a tutorial of his, on making your own Keyer controls.
Best of luck.

Sent from my iPhone using Tapatalk

Are you talking about blurring the RGB channels, Alpha or both?

Try using the matte control node after the erode/dilate node. You can then blur and contract/expand the alpha only. Depending on what you are trying to achieve this may work better and negate the need for an erode node.