CFL from UDT (and UDO)

Hello everyone.

I have the following problem.I have an matrix in a user's form that has 4 columns

Col_1 = Material Code
Col_2 = Material Name
Col_3 = Submaterial Code
Col_4 = Submaterial Name

I created a UDO called UDO_MATERIALS that associates two tables (master data and master data lines), this way in the UDO form I can fill my data. In this matrix I linked the first column with this UDO and works ok. It shows the CFL with the possible values. So far so good.
The problem is that in the Col_3 I should place another CFL for submaterials where, depending on the material you select in the first column, I'll show the possible options.

I can not do formatted searchs (the client does not allow it) I read somewhere that it could be done by defining a new table of submaterials and create a UDO with it. And then in the table of submaterials of the first UDO (UDO_MATERIALES) add a user field to link with the new UDO.
The problem is that when creating the user field does not give me the option to link it to a UDO.

Any ideas?


Thank you so much