Here’s a possible solution:
1. Within a fortnight prior to the elections, all parties must announce publicly all their allies in a post poll scenario whose numbers they expect to add up to 272.
2. This will formalize how many ‘fronts’ there could potentially be. Of course theoritically this could mean 10-20 fronts, but some of these combinations will be too impractical to get any credence, and eventually there would be deals worked out to reduce that number.
3. A party may well say that it will support two ‘fronts’, say F1 and the F2. In that case, the voters would reward / punish the ambivalence of the party as they deem fit.
4. Up to the last fortnight all sorts of deals / combinations could be worked out by the various parties, but none after the deadline.
5. Post elections, if there is a hung parliament, individual fronts would have the freedom to coalesce with any other existing front to get to a total of 272. However, this would be allowed ONLY if the entire front agrees to coalesce.
6. The formation will be binding for a fixed period – say one year. After that one year, all parties become independent again, in the sense that they can withdraw support from a front on the basis of some point of disagreement. This ensures that the ruling coalition doesn’t get complacent once the figure of 272 is reached.