Restrict use of GL account on Invoices

Hi,

We're having some issues where AP users are entering invoices with item lines using the VAT GL account, instead of tax lines.

For example - VAT account is 22222

Invoice 119 out of which 19 is VAT is entered

Item 1 - 100 on account 55555 (Stationary...)

Item 2 - 19 on account 22222 (VAT)

Tax - 0

we're looking to have Item 1 - 100 on 55555, Tax - 19 on 22222

We want to restrict use of 22222 so that this is only used as a Tax item and they are force to calculate tax on invoices rather than entering this as an item.

Is there any way we can achieve that?

Hope this makes sense,