"Is it possible to map a loan account to two accounts viz.: Long term and short term?"
At present, it is not possible to map a single ledger under two subheads.
What you can do is to simply pass a JV in Tally by debiting the Loan account and crediting 'Current Maturities' ledger.
Thereafter, you may proceed to classify the Loan Account balances under Long Term Borrowings group and Current Maturities under Current Maturities subhead.