That is a very good question. :)
I don't think there is a term for that type of attack as far as I know. However, I think it can be considered a pin if the position is right, and the same goes for a skewer. Sometimes it is best for that first piece under attack to move out of the was to avoid a big loss, and sometimes it is best for that piece to stay put. There are also times where you have a choice on which way you want out of it. :)
We know that a pin is when a less valuable piece is attacked by a long rang piece while defending a higher valuable piece such that movement of the piece subjects the more valuable piece to attack.
We know that a skewer is the opposite, in terms of piece value attacked.
But what if the pieces are of same value? For example, a bishop attacking a rook on a diagonal with another rook on same diagonal with no pieces between the rooks (but not forked).
Is there a special term for this?