Match substring

I have a table that looks like this:

Transaction	Type
TRANSFERRED FROM VS 123-4567890-1
REDEMPTION FROM CORE ACCOUNT
TRANSFER OF ASSETS WR76543210
TRANSFER OF ASSETS WR81234761
YOU SOLD CONF:13004NKGOZ 0
TRANSFERRED FROM VS 456-1246019-1

and another table that looks like this:

Key	Value
TRANSFERRED FROM	External Flow
TRANSFER OF ASSETS	External Flow
YOU SOLD	Sale

I'm trying to create a formula that will find the key that is a substring of each transaction (if there is one). So with the formula applied to the type column of the source table it should look like this:

Transaction	Type
TRANSFERRED FROM VS 123-4567890-1	External Flow
REDEMPTION FROM CORE ACCOUNT
TRANSFER OF ASSETS WR76543210	External Flow
TRANSFER OF ASSETS WR81234761	External Flow
YOU SOLD CONF:13004NKGOZ 0	Sale
TRANSFERRED FROM VS 456-1246019-1	External Flow

Note that you can't just use fuzzy matching (i.e. MATCH with match_type 1) because if none of the the values are a substring of the transaction in question, the type should be blank.

Any ideas? Strongly prefer a formula rather than a macro, if possible. Thanks!